mirror of
https://github.com/rust-lang/rustlings.git
synced 2026-01-11 13:19:18 +00:00
Updating rustlings branch with completed exercises
This commit is contained in:
parent
9acefe8b3a
commit
a2c56cb5b8
2
Cargo.lock
generated
2
Cargo.lock
generated
@ -459,7 +459,7 @@ checksum = "f497285884f3fcff424ffc933e56d7cbca511def0c9831a7f9b5f6153e3cc89b"
|
|||||||
|
|
||||||
[[package]]
|
[[package]]
|
||||||
name = "rustlings"
|
name = "rustlings"
|
||||||
version = "5.4.0"
|
version = "5.4.1"
|
||||||
dependencies = [
|
dependencies = [
|
||||||
"argh",
|
"argh",
|
||||||
"assert_cmd",
|
"assert_cmd",
|
||||||
|
|||||||
@ -1,11 +1,14 @@
|
|||||||
// enums1.rs
|
// enums1.rs
|
||||||
// No hints this time! ;)
|
// No hints this time! ;)
|
||||||
|
|
||||||
// I AM NOT DONE
|
|
||||||
|
|
||||||
#[derive(Debug)]
|
#[derive(Debug)]
|
||||||
enum Message {
|
enum Message {
|
||||||
// TODO: define a few types of messages as used below
|
// TODO: define a few types of messages as used below
|
||||||
|
Quit,
|
||||||
|
Echo,
|
||||||
|
Move,
|
||||||
|
ChangeColor,
|
||||||
}
|
}
|
||||||
|
|
||||||
fn main() {
|
fn main() {
|
||||||
|
|||||||
@ -1,11 +1,14 @@
|
|||||||
// enums2.rs
|
// enums2.rs
|
||||||
// Execute `rustlings hint enums2` or use the `hint` watch subcommand for a hint.
|
// Execute `rustlings hint enums2` or use the `hint` watch subcommand for a hint.
|
||||||
|
|
||||||
// I AM NOT DONE
|
|
||||||
|
|
||||||
#[derive(Debug)]
|
#[derive(Debug)]
|
||||||
enum Message {
|
enum Message {
|
||||||
// TODO: define the different variants used below
|
// TODO: define the different variants used below
|
||||||
|
Move{x:usize, y:usize},
|
||||||
|
Echo(String),
|
||||||
|
ChangeColor(usize, usize, usize),
|
||||||
|
Quit,
|
||||||
}
|
}
|
||||||
|
|
||||||
impl Message {
|
impl Message {
|
||||||
|
|||||||
@ -2,10 +2,15 @@
|
|||||||
// Address all the TODOs to make the tests pass!
|
// Address all the TODOs to make the tests pass!
|
||||||
// Execute `rustlings hint enums3` or use the `hint` watch subcommand for a hint.
|
// Execute `rustlings hint enums3` or use the `hint` watch subcommand for a hint.
|
||||||
|
|
||||||
// I AM NOT DONE
|
|
||||||
|
use core::panic;
|
||||||
|
|
||||||
enum Message {
|
enum Message {
|
||||||
// TODO: implement the message variant types based on their usage below
|
// TODO: implement the message variant types based on their usage below
|
||||||
|
ChangeColor(u8, u8, u8),
|
||||||
|
Echo(String),
|
||||||
|
Move(Point),
|
||||||
|
Quit,
|
||||||
}
|
}
|
||||||
|
|
||||||
struct Point {
|
struct Point {
|
||||||
@ -39,9 +44,15 @@ impl State {
|
|||||||
fn process(&mut self, message: Message) {
|
fn process(&mut self, message: Message) {
|
||||||
// TODO: create a match expression to process the different message variants
|
// TODO: create a match expression to process the different message variants
|
||||||
// Remember: When passing a tuple as a function argument, you'll need extra parentheses: fn function((t, u, p, l, e))
|
// Remember: When passing a tuple as a function argument, you'll need extra parentheses: fn function((t, u, p, l, e))
|
||||||
|
match message {
|
||||||
|
Message::ChangeColor(r, g, b) => self.change_color((r,g,b)),
|
||||||
|
Message::Echo(string) => self.echo(string),
|
||||||
|
Message::Move(point) => self.move_position(point),
|
||||||
|
Message::Quit => self.quit(),
|
||||||
|
|
||||||
|
}
|
||||||
}
|
}
|
||||||
}
|
}
|
||||||
|
|
||||||
#[cfg(test)]
|
#[cfg(test)]
|
||||||
mod tests {
|
mod tests {
|
||||||
use super::*;
|
use super::*;
|
||||||
@ -63,4 +74,6 @@ mod tests {
|
|||||||
assert_eq!(state.position.y, 15);
|
assert_eq!(state.position.y, 15);
|
||||||
assert_eq!(state.quit, true);
|
assert_eq!(state.quit, true);
|
||||||
}
|
}
|
||||||
|
|
||||||
|
|
||||||
}
|
}
|
||||||
|
|||||||
@ -5,14 +5,13 @@
|
|||||||
// construct to `Option` that can be used to express error conditions. Let's use it!
|
// construct to `Option` that can be used to express error conditions. Let's use it!
|
||||||
// Execute `rustlings hint errors1` or use the `hint` watch subcommand for a hint.
|
// Execute `rustlings hint errors1` or use the `hint` watch subcommand for a hint.
|
||||||
|
|
||||||
// I AM NOT DONE
|
|
||||||
|
|
||||||
pub fn generate_nametag_text(name: String) -> Option<String> {
|
|
||||||
|
pub fn generate_nametag_text(name: String) -> Result<String, String> {
|
||||||
if name.is_empty() {
|
if name.is_empty() {
|
||||||
// Empty names aren't allowed.
|
Err(format!("`name` was empty; it must be nonempty."))
|
||||||
None
|
|
||||||
} else {
|
} else {
|
||||||
Some(format!("Hi! My name is {}", name))
|
Ok(format!("Hi! My name is {}", name))
|
||||||
}
|
}
|
||||||
}
|
}
|
||||||
|
|
||||||
|
|||||||
@ -17,16 +17,20 @@
|
|||||||
// one is a lot shorter!
|
// one is a lot shorter!
|
||||||
// Execute `rustlings hint errors2` or use the `hint` watch subcommand for a hint.
|
// Execute `rustlings hint errors2` or use the `hint` watch subcommand for a hint.
|
||||||
|
|
||||||
// I AM NOT DONE
|
|
||||||
|
|
||||||
use std::num::ParseIntError;
|
use std::num::ParseIntError;
|
||||||
|
|
||||||
pub fn total_cost(item_quantity: &str) -> Result<i32, ParseIntError> {
|
pub fn total_cost(item_quantity: &str) -> Result<i32, ParseIntError> {
|
||||||
let processing_fee = 1;
|
let processing_fee = 1;
|
||||||
let cost_per_item = 5;
|
let cost_per_item = 5;
|
||||||
let qty = item_quantity.parse::<i32>();
|
Ok(item_quantity.parse::<i32>()? * cost_per_item + processing_fee)
|
||||||
|
// match item_quantity.parse::<i32>() {
|
||||||
|
// Ok(qty) => Ok(qty * cost_per_item + processing_fee),
|
||||||
|
// Err(err) => Err(err)
|
||||||
|
// }
|
||||||
|
|
||||||
Ok(qty * cost_per_item + processing_fee)
|
|
||||||
}
|
}
|
||||||
|
|
||||||
#[cfg(test)]
|
#[cfg(test)]
|
||||||
|
|||||||
@ -4,11 +4,10 @@
|
|||||||
// Why not? What should we do to fix it?
|
// Why not? What should we do to fix it?
|
||||||
// Execute `rustlings hint errors3` or use the `hint` watch subcommand for a hint.
|
// Execute `rustlings hint errors3` or use the `hint` watch subcommand for a hint.
|
||||||
|
|
||||||
// I AM NOT DONE
|
|
||||||
|
|
||||||
use std::num::ParseIntError;
|
use std::{num::ParseIntError,error::Error};
|
||||||
|
|
||||||
fn main() {
|
fn main() -> Result<(), Box<dyn Error> > {
|
||||||
let mut tokens = 100;
|
let mut tokens = 100;
|
||||||
let pretend_user_input = "8";
|
let pretend_user_input = "8";
|
||||||
|
|
||||||
@ -20,6 +19,7 @@ fn main() {
|
|||||||
tokens -= cost;
|
tokens -= cost;
|
||||||
println!("You now have {} tokens.", tokens);
|
println!("You now have {} tokens.", tokens);
|
||||||
}
|
}
|
||||||
|
Ok(())
|
||||||
}
|
}
|
||||||
|
|
||||||
pub fn total_cost(item_quantity: &str) -> Result<i32, ParseIntError> {
|
pub fn total_cost(item_quantity: &str) -> Result<i32, ParseIntError> {
|
||||||
|
|||||||
@ -1,7 +1,6 @@
|
|||||||
// errors4.rs
|
// errors4.rs
|
||||||
// Execute `rustlings hint errors4` or use the `hint` watch subcommand for a hint.
|
// Execute `rustlings hint errors4` or use the `hint` watch subcommand for a hint.
|
||||||
|
|
||||||
// I AM NOT DONE
|
|
||||||
|
|
||||||
#[derive(PartialEq, Debug)]
|
#[derive(PartialEq, Debug)]
|
||||||
struct PositiveNonzeroInteger(u64);
|
struct PositiveNonzeroInteger(u64);
|
||||||
@ -15,7 +14,11 @@ enum CreationError {
|
|||||||
impl PositiveNonzeroInteger {
|
impl PositiveNonzeroInteger {
|
||||||
fn new(value: i64) -> Result<PositiveNonzeroInteger, CreationError> {
|
fn new(value: i64) -> Result<PositiveNonzeroInteger, CreationError> {
|
||||||
// Hmm...? Why is this only returning an Ok value?
|
// Hmm...? Why is this only returning an Ok value?
|
||||||
Ok(PositiveNonzeroInteger(value as u64))
|
|
||||||
|
if value.is_negative() {Err(CreationError::Negative)}
|
||||||
|
else if value.is_positive() {Ok(PositiveNonzeroInteger(value as u64))}
|
||||||
|
else {Err(CreationError::Zero)}
|
||||||
|
|
||||||
}
|
}
|
||||||
}
|
}
|
||||||
|
|
||||||
|
|||||||
@ -16,14 +16,14 @@
|
|||||||
|
|
||||||
// Execute `rustlings hint errors5` or use the `hint` watch subcommand for a hint.
|
// Execute `rustlings hint errors5` or use the `hint` watch subcommand for a hint.
|
||||||
|
|
||||||
// I AM NOT DONE
|
|
||||||
|
|
||||||
use std::error;
|
use std::error;
|
||||||
|
use std::error::Error;
|
||||||
use std::fmt;
|
use std::fmt;
|
||||||
use std::num::ParseIntError;
|
use std::num::ParseIntError;
|
||||||
|
|
||||||
// TODO: update the return type of `main()` to make this compile.
|
// TODO: update the return type of `main()` to make this compile.
|
||||||
fn main() -> Result<(), Box<dyn ???>> {
|
fn main() -> Result<(), Box<dyn Error>> {
|
||||||
let pretend_user_input = "42";
|
let pretend_user_input = "42";
|
||||||
let x: i64 = pretend_user_input.parse()?;
|
let x: i64 = pretend_user_input.parse()?;
|
||||||
println!("output={:?}", PositiveNonzeroInteger::new(x)?);
|
println!("output={:?}", PositiveNonzeroInteger::new(x)?);
|
||||||
|
|||||||
@ -8,7 +8,6 @@
|
|||||||
|
|
||||||
// Execute `rustlings hint errors6` or use the `hint` watch subcommand for a hint.
|
// Execute `rustlings hint errors6` or use the `hint` watch subcommand for a hint.
|
||||||
|
|
||||||
// I AM NOT DONE
|
|
||||||
|
|
||||||
use std::num::ParseIntError;
|
use std::num::ParseIntError;
|
||||||
|
|
||||||
@ -24,14 +23,25 @@ impl ParsePosNonzeroError {
|
|||||||
ParsePosNonzeroError::Creation(err)
|
ParsePosNonzeroError::Creation(err)
|
||||||
}
|
}
|
||||||
// TODO: add another error conversion function here.
|
// TODO: add another error conversion function here.
|
||||||
// fn from_parseint...
|
fn from_parseint(err: ParseIntError) -> ParsePosNonzeroError {
|
||||||
|
ParsePosNonzeroError::ParseInt(err)
|
||||||
|
}
|
||||||
}
|
}
|
||||||
|
|
||||||
fn parse_pos_nonzero(s: &str) -> Result<PositiveNonzeroInteger, ParsePosNonzeroError> {
|
fn parse_pos_nonzero(s: &str) -> Result<PositiveNonzeroInteger, ParsePosNonzeroError> {
|
||||||
// TODO: change this to return an appropriate error instead of panicking
|
// TODO: change this to return an appropriate error instead of panicking
|
||||||
// when `parse()` returns an error.
|
// when `parse()` returns an error.
|
||||||
let x: i64 = s.parse().unwrap();
|
match s.parse::<i64>().map_err(ParsePosNonzeroError::from_parseint) {
|
||||||
PositiveNonzeroInteger::new(x).map_err(ParsePosNonzeroError::from_creation)
|
Ok(x) => if x.is_positive() {
|
||||||
|
Ok(PositiveNonzeroInteger(x.try_into().unwrap()))
|
||||||
|
} else if x.is_negative() {
|
||||||
|
Err(ParsePosNonzeroError::from_creation(CreationError::Negative))
|
||||||
|
} else {
|
||||||
|
Err(ParsePosNonzeroError::from_creation(CreationError::Zero))
|
||||||
|
}
|
||||||
|
Err(err) => Err(err)
|
||||||
|
}
|
||||||
|
|
||||||
}
|
}
|
||||||
|
|
||||||
// Don't change anything below this line.
|
// Don't change anything below this line.
|
||||||
|
|||||||
@ -1,8 +1,9 @@
|
|||||||
// functions1.rs
|
// functions1.rs
|
||||||
// Execute `rustlings hint functions1` or use the `hint` watch subcommand for a hint.
|
// Execute `rustlings hint functions1` or use the `hint` watch subcommand for a hint.
|
||||||
|
|
||||||
// I AM NOT DONE
|
|
||||||
|
|
||||||
fn main() {
|
fn main() {
|
||||||
call_me();
|
call_me();
|
||||||
}
|
}
|
||||||
|
|
||||||
|
fn call_me() {}
|
||||||
@ -1,13 +1,13 @@
|
|||||||
// functions2.rs
|
// functions2.rs
|
||||||
// Execute `rustlings hint functions2` or use the `hint` watch subcommand for a hint.
|
// Execute `rustlings hint functions2` or use the `hint` watch subcommand for a hint.
|
||||||
|
|
||||||
// I AM NOT DONE
|
|
||||||
|
|
||||||
fn main() {
|
fn main() {
|
||||||
call_me(3);
|
call_me(3);
|
||||||
}
|
}
|
||||||
|
|
||||||
fn call_me(num:) {
|
fn call_me(num: i32) {
|
||||||
for i in 0..num {
|
for i in 0..num {
|
||||||
println!("Ring! Call number {}", i + 1);
|
println!("Ring! Call number {}", i + 1);
|
||||||
}
|
}
|
||||||
|
|||||||
@ -1,10 +1,9 @@
|
|||||||
// functions3.rs
|
// functions3.rs
|
||||||
// Execute `rustlings hint functions3` or use the `hint` watch subcommand for a hint.
|
// Execute `rustlings hint functions3` or use the `hint` watch subcommand for a hint.
|
||||||
|
|
||||||
// I AM NOT DONE
|
|
||||||
|
|
||||||
fn main() {
|
fn main() {
|
||||||
call_me();
|
call_me(2);
|
||||||
}
|
}
|
||||||
|
|
||||||
fn call_me(num: u32) {
|
fn call_me(num: u32) {
|
||||||
|
|||||||
@ -7,14 +7,13 @@
|
|||||||
// in the signatures for now. If anything, this is a good way to peek ahead
|
// in the signatures for now. If anything, this is a good way to peek ahead
|
||||||
// to future exercises!)
|
// to future exercises!)
|
||||||
|
|
||||||
// I AM NOT DONE
|
|
||||||
|
|
||||||
fn main() {
|
fn main() {
|
||||||
let original_price = 51;
|
let original_price = 51;
|
||||||
println!("Your sale price is {}", sale_price(original_price));
|
println!("Your sale price is {}", sale_price(original_price));
|
||||||
}
|
}
|
||||||
|
|
||||||
fn sale_price(price: i32) -> {
|
fn sale_price(price: i32) -> i32 {
|
||||||
if is_even(price) {
|
if is_even(price) {
|
||||||
price - 10
|
price - 10
|
||||||
} else {
|
} else {
|
||||||
|
|||||||
@ -1,7 +1,7 @@
|
|||||||
// functions5.rs
|
// functions5.rs
|
||||||
// Execute `rustlings hint functions5` or use the `hint` watch subcommand for a hint.
|
// Execute `rustlings hint functions5` or use the `hint` watch subcommand for a hint.
|
||||||
|
|
||||||
// I AM NOT DONE
|
|
||||||
|
|
||||||
fn main() {
|
fn main() {
|
||||||
let answer = square(3);
|
let answer = square(3);
|
||||||
@ -9,5 +9,5 @@ fn main() {
|
|||||||
}
|
}
|
||||||
|
|
||||||
fn square(num: i32) -> i32 {
|
fn square(num: i32) -> i32 {
|
||||||
num * num;
|
num * num
|
||||||
}
|
}
|
||||||
|
|||||||
@ -3,9 +3,9 @@
|
|||||||
|
|
||||||
// Execute `rustlings hint generics1` or use the `hint` watch subcommand for a hint.
|
// Execute `rustlings hint generics1` or use the `hint` watch subcommand for a hint.
|
||||||
|
|
||||||
// I AM NOT DONE
|
|
||||||
|
|
||||||
fn main() {
|
fn main() {
|
||||||
let mut shopping_list: Vec<?> = Vec::new();
|
let mut shopping_list: Vec<&str> = Vec::new();
|
||||||
shopping_list.push("milk");
|
shopping_list.push("milk");
|
||||||
}
|
}
|
||||||
|
|||||||
@ -3,14 +3,13 @@
|
|||||||
|
|
||||||
// Execute `rustlings hint generics2` or use the `hint` watch subcommand for a hint.
|
// Execute `rustlings hint generics2` or use the `hint` watch subcommand for a hint.
|
||||||
|
|
||||||
// I AM NOT DONE
|
|
||||||
|
|
||||||
struct Wrapper {
|
struct Wrapper<T> {
|
||||||
value: u32,
|
value: T,
|
||||||
}
|
}
|
||||||
|
|
||||||
impl Wrapper {
|
impl <T> Wrapper<T> {
|
||||||
pub fn new(value: u32) -> Self {
|
pub fn new(value: T) -> Self {
|
||||||
Wrapper { value }
|
Wrapper { value }
|
||||||
}
|
}
|
||||||
}
|
}
|
||||||
|
|||||||
@ -10,15 +10,16 @@
|
|||||||
//
|
//
|
||||||
// Execute `rustlings hint hashmaps1` or use the `hint` watch subcommand for a hint.
|
// Execute `rustlings hint hashmaps1` or use the `hint` watch subcommand for a hint.
|
||||||
|
|
||||||
// I AM NOT DONE
|
|
||||||
|
|
||||||
use std::collections::HashMap;
|
use std::collections::HashMap;
|
||||||
|
|
||||||
fn fruit_basket() -> HashMap<String, u32> {
|
fn fruit_basket() -> HashMap<String, u32> {
|
||||||
let mut basket = // TODO: declare your hash map here.
|
let mut basket = HashMap::new();
|
||||||
|
|
||||||
// Two bananas are already given for you :)
|
// Two bananas are already given for you :)
|
||||||
basket.insert(String::from("banana"), 2);
|
basket.insert(String::from("banana"), 2);
|
||||||
|
basket.insert(String::from("blueberries"), 5);
|
||||||
|
basket.insert(String::from("apples"), 3);
|
||||||
|
|
||||||
// TODO: Put more fruits in your basket here.
|
// TODO: Put more fruits in your basket here.
|
||||||
|
|
||||||
|
|||||||
@ -11,7 +11,6 @@
|
|||||||
//
|
//
|
||||||
// Execute `rustlings hint hashmaps2` or use the `hint` watch subcommand for a hint.
|
// Execute `rustlings hint hashmaps2` or use the `hint` watch subcommand for a hint.
|
||||||
|
|
||||||
// I AM NOT DONE
|
|
||||||
|
|
||||||
use std::collections::HashMap;
|
use std::collections::HashMap;
|
||||||
|
|
||||||
@ -34,9 +33,9 @@ fn fruit_basket(basket: &mut HashMap<Fruit, u32>) {
|
|||||||
];
|
];
|
||||||
|
|
||||||
for fruit in fruit_kinds {
|
for fruit in fruit_kinds {
|
||||||
// TODO: Put new fruits if not already present. Note that you
|
if let None=basket.get(&fruit) {
|
||||||
// are not allowed to put any type of fruit that's already
|
basket.insert(fruit, 1);
|
||||||
// present!
|
}
|
||||||
}
|
}
|
||||||
}
|
}
|
||||||
|
|
||||||
|
|||||||
@ -14,7 +14,6 @@
|
|||||||
|
|
||||||
// Execute `rustlings hint hashmaps3` or use the `hint` watch subcommand for a hint.
|
// Execute `rustlings hint hashmaps3` or use the `hint` watch subcommand for a hint.
|
||||||
|
|
||||||
// I AM NOT DONE
|
|
||||||
|
|
||||||
use std::collections::HashMap;
|
use std::collections::HashMap;
|
||||||
|
|
||||||
@ -31,15 +30,28 @@ fn build_scores_table(results: String) -> HashMap<String, Team> {
|
|||||||
|
|
||||||
for r in results.lines() {
|
for r in results.lines() {
|
||||||
let v: Vec<&str> = r.split(',').collect();
|
let v: Vec<&str> = r.split(',').collect();
|
||||||
let team_1_name = v[0].to_string();
|
let mut team_1 = Team {
|
||||||
let team_1_score: u8 = v[2].parse().unwrap();
|
name:v[0].to_string(),
|
||||||
let team_2_name = v[1].to_string();
|
goals_scored:v[2].parse().unwrap(),
|
||||||
let team_2_score: u8 = v[3].parse().unwrap();
|
goals_conceded:v[3].parse().unwrap()};
|
||||||
|
let mut team_2 = Team {
|
||||||
|
name:v[1].to_string(),
|
||||||
|
goals_scored: v[3].parse().unwrap(),
|
||||||
|
goals_conceded: v[2].parse().unwrap()};
|
||||||
|
|
||||||
// TODO: Populate the scores table with details extracted from the
|
// TODO: Populate the scores table with details extracted from the
|
||||||
// current line. Keep in mind that goals scored by team_1
|
// current line. Keep in mind that goals scored by team_1
|
||||||
// will be the number of goals conceded from team_2, and similarly
|
// will be the number of goals conceded from team_2, and similarly
|
||||||
// goals scored by team_2 will be the number of goals conceded by
|
// goals scored by team_2 will be the number of goals conceded by
|
||||||
// team_1.
|
// team_1.
|
||||||
|
for mut team in [team_1, team_2] {
|
||||||
|
if let Some((_,team_existing_scores)) = scores.get_key_value(&team.name) {
|
||||||
|
team.goals_scored += team_existing_scores.goals_scored;
|
||||||
|
team.goals_conceded += team_existing_scores.goals_conceded;
|
||||||
|
}
|
||||||
|
scores.insert(team.name.to_string(), team);
|
||||||
|
}
|
||||||
|
|
||||||
}
|
}
|
||||||
scores
|
scores
|
||||||
}
|
}
|
||||||
|
|||||||
@ -1,13 +1,12 @@
|
|||||||
// if1.rs
|
// if1.rs
|
||||||
// Execute `rustlings hint if1` or use the `hint` watch subcommand for a hint.
|
// Execute `rustlings hint if1` or use the `hint` watch subcommand for a hint.
|
||||||
|
|
||||||
// I AM NOT DONE
|
|
||||||
|
|
||||||
pub fn bigger(a: i32, b: i32) -> i32 {
|
pub fn bigger(a: i32, b: i32) -> i32 {
|
||||||
// Complete this function to return the bigger number!
|
if a>b {a}
|
||||||
// Do not use:
|
else if b>a {b}
|
||||||
// - another function call
|
else {panic!("numbers are the same!")}
|
||||||
// - additional variables
|
|
||||||
}
|
}
|
||||||
|
|
||||||
// Don't mind this for now :)
|
// Don't mind this for now :)
|
||||||
|
|||||||
@ -4,14 +4,15 @@
|
|||||||
// Step 2: Get the bar_for_fuzz and default_to_baz tests passing!
|
// Step 2: Get the bar_for_fuzz and default_to_baz tests passing!
|
||||||
// Execute `rustlings hint if2` or use the `hint` watch subcommand for a hint.
|
// Execute `rustlings hint if2` or use the `hint` watch subcommand for a hint.
|
||||||
|
|
||||||
// I AM NOT DONE
|
|
||||||
|
|
||||||
pub fn foo_if_fizz(fizzish: &str) -> &str {
|
pub fn foo_if_fizz(fizzish: &str) -> &str {
|
||||||
if fizzish == "fizz" {
|
match fizzish {
|
||||||
"foo"
|
"fizz" => "foo",
|
||||||
} else {
|
"fuzz" => "bar",
|
||||||
1
|
_ => "baz",
|
||||||
}
|
}
|
||||||
|
|
||||||
}
|
}
|
||||||
|
|
||||||
// No test changes needed!
|
// No test changes needed!
|
||||||
|
|||||||
@ -9,8 +9,6 @@
|
|||||||
// when you change one of the lines below! Try adding a `println!` line, or try changing
|
// when you change one of the lines below! Try adding a `println!` line, or try changing
|
||||||
// what it outputs in your terminal. Try removing a semicolon and see what happens!
|
// what it outputs in your terminal. Try removing a semicolon and see what happens!
|
||||||
|
|
||||||
// I AM NOT DONE
|
|
||||||
|
|
||||||
fn main() {
|
fn main() {
|
||||||
println!("Hello and");
|
println!("Hello and");
|
||||||
println!(r#" welcome to... "#);
|
println!(r#" welcome to... "#);
|
||||||
|
|||||||
@ -2,8 +2,8 @@
|
|||||||
// Make the code print a greeting to the world.
|
// Make the code print a greeting to the world.
|
||||||
// Execute `rustlings hint intro2` or use the `hint` watch subcommand for a hint.
|
// Execute `rustlings hint intro2` or use the `hint` watch subcommand for a hint.
|
||||||
|
|
||||||
// I AM NOT DONE
|
|
||||||
|
|
||||||
fn main() {
|
fn main() {
|
||||||
println!("Hello {}!");
|
println!("Hello world!");
|
||||||
}
|
}
|
||||||
|
|||||||
@ -8,17 +8,16 @@
|
|||||||
//
|
//
|
||||||
// Execute `rustlings hint iterators1` or use the `hint` watch subcommand for a hint.
|
// Execute `rustlings hint iterators1` or use the `hint` watch subcommand for a hint.
|
||||||
|
|
||||||
// I AM NOT DONE
|
|
||||||
|
|
||||||
fn main() {
|
fn main() {
|
||||||
let my_fav_fruits = vec!["banana", "custard apple", "avocado", "peach", "raspberry"];
|
let my_fav_fruits = vec!["banana", "custard apple", "avocado", "peach", "raspberry"];
|
||||||
|
|
||||||
let mut my_iterable_fav_fruits = ???; // TODO: Step 1
|
let mut my_iterable_fav_fruits = my_fav_fruits.iter(); // TODO: Step 1
|
||||||
|
|
||||||
assert_eq!(my_iterable_fav_fruits.next(), Some(&"banana"));
|
assert_eq!(my_iterable_fav_fruits.next(), Some(&"banana"));
|
||||||
assert_eq!(my_iterable_fav_fruits.next(), ???); // TODO: Step 2
|
assert_eq!(my_iterable_fav_fruits.next(), Some(&"custard apple")); // TODO: Step 2
|
||||||
assert_eq!(my_iterable_fav_fruits.next(), Some(&"avocado"));
|
assert_eq!(my_iterable_fav_fruits.next(), Some(&"avocado"));
|
||||||
assert_eq!(my_iterable_fav_fruits.next(), ???); // TODO: Step 3
|
assert_eq!(my_iterable_fav_fruits.next(), Some(&"peach")); // TODO: Step 3
|
||||||
assert_eq!(my_iterable_fav_fruits.next(), Some(&"raspberry"));
|
assert_eq!(my_iterable_fav_fruits.next(), Some(&"raspberry"));
|
||||||
assert_eq!(my_iterable_fav_fruits.next(), ???); // TODO: Step 4
|
assert_eq!(my_iterable_fav_fruits.next(), None); // TODO: Step 4
|
||||||
}
|
}
|
||||||
|
|||||||
@ -3,7 +3,6 @@
|
|||||||
// can offer. Follow the steps to complete the exercise.
|
// can offer. Follow the steps to complete the exercise.
|
||||||
// Execute `rustlings hint iterators2` or use the `hint` watch subcommand for a hint.
|
// Execute `rustlings hint iterators2` or use the `hint` watch subcommand for a hint.
|
||||||
|
|
||||||
// I AM NOT DONE
|
|
||||||
|
|
||||||
// Step 1.
|
// Step 1.
|
||||||
// Complete the `capitalize_first` function.
|
// Complete the `capitalize_first` function.
|
||||||
@ -12,7 +11,7 @@ pub fn capitalize_first(input: &str) -> String {
|
|||||||
let mut c = input.chars();
|
let mut c = input.chars();
|
||||||
match c.next() {
|
match c.next() {
|
||||||
None => String::new(),
|
None => String::new(),
|
||||||
Some(first) => ???,
|
Some(first) => first.to_uppercase().to_string()+c.as_str()
|
||||||
}
|
}
|
||||||
}
|
}
|
||||||
|
|
||||||
@ -21,7 +20,15 @@ pub fn capitalize_first(input: &str) -> String {
|
|||||||
// Return a vector of strings.
|
// Return a vector of strings.
|
||||||
// ["hello", "world"] -> ["Hello", "World"]
|
// ["hello", "world"] -> ["Hello", "World"]
|
||||||
pub fn capitalize_words_vector(words: &[&str]) -> Vec<String> {
|
pub fn capitalize_words_vector(words: &[&str]) -> Vec<String> {
|
||||||
vec![]
|
let mut capitalized_words_vec:Vec<String>= Vec::new();
|
||||||
|
// for word in words {
|
||||||
|
// capitalized_words_vec.push(capitalize_first(&word));
|
||||||
|
// }
|
||||||
|
// capitalized_words_vec
|
||||||
|
let iter = words.iter();
|
||||||
|
iter.for_each(|word| capitalized_words_vec.push(capitalize_first(word)));
|
||||||
|
capitalized_words_vec
|
||||||
|
|
||||||
}
|
}
|
||||||
|
|
||||||
// Step 3.
|
// Step 3.
|
||||||
@ -29,7 +36,13 @@ pub fn capitalize_words_vector(words: &[&str]) -> Vec<String> {
|
|||||||
// Return a single string.
|
// Return a single string.
|
||||||
// ["hello", " ", "world"] -> "Hello World"
|
// ["hello", " ", "world"] -> "Hello World"
|
||||||
pub fn capitalize_words_string(words: &[&str]) -> String {
|
pub fn capitalize_words_string(words: &[&str]) -> String {
|
||||||
String::new()
|
let mut capitalized_words_string = String::new();
|
||||||
|
// for word in words {
|
||||||
|
// capitalized_words_string += capitalize_first(word).as_str();
|
||||||
|
// }
|
||||||
|
let iter = words.iter();
|
||||||
|
iter.for_each(|word| capitalized_words_string += capitalize_first(word).as_str());
|
||||||
|
capitalized_words_string
|
||||||
}
|
}
|
||||||
|
|
||||||
#[cfg(test)]
|
#[cfg(test)]
|
||||||
|
|||||||
@ -6,7 +6,9 @@
|
|||||||
// list_of_results functions.
|
// list_of_results functions.
|
||||||
// Execute `rustlings hint iterators3` or use the `hint` watch subcommand for a hint.
|
// Execute `rustlings hint iterators3` or use the `hint` watch subcommand for a hint.
|
||||||
|
|
||||||
// I AM NOT DONE
|
use std::result::Result;
|
||||||
|
|
||||||
|
|
||||||
|
|
||||||
#[derive(Debug, PartialEq, Eq)]
|
#[derive(Debug, PartialEq, Eq)]
|
||||||
pub enum DivisionError {
|
pub enum DivisionError {
|
||||||
@ -23,21 +25,51 @@ pub struct NotDivisibleError {
|
|||||||
// Calculate `a` divided by `b` if `a` is evenly divisible by `b`.
|
// Calculate `a` divided by `b` if `a` is evenly divisible by `b`.
|
||||||
// Otherwise, return a suitable error.
|
// Otherwise, return a suitable error.
|
||||||
pub fn divide(a: i32, b: i32) -> Result<i32, DivisionError> {
|
pub fn divide(a: i32, b: i32) -> Result<i32, DivisionError> {
|
||||||
todo!();
|
if b==0 {
|
||||||
|
Err(DivisionError::DivideByZero)
|
||||||
|
}
|
||||||
|
else if a%b==0 {
|
||||||
|
Ok(a/b)
|
||||||
|
}
|
||||||
|
else {
|
||||||
|
Err(DivisionError::NotDivisible(NotDivisibleError { dividend: a, divisor: b}))
|
||||||
|
}
|
||||||
|
|
||||||
}
|
}
|
||||||
|
|
||||||
// Complete the function and return a value of the correct type so the test passes.
|
// Complete the function and return a value of the correct type so the test passes.
|
||||||
// Desired output: Ok([1, 11, 1426, 3])
|
// Desired output: Ok([1, 11, 1426, 3])
|
||||||
fn result_with_list() -> () {
|
fn result_with_list() -> Result<Vec<i32>,()> {
|
||||||
let numbers = vec![27, 297, 38502, 81];
|
let numbers = vec![27, 297, 38502, 81];
|
||||||
let division_results = numbers.into_iter().map(|n| divide(n, 27));
|
Ok(numbers.into_iter().map(|n| divide(n, 27).unwrap()).collect())
|
||||||
|
|
||||||
|
// let mut divided_numbers: Vec<i32> = Vec::new();
|
||||||
|
// for result in division_results {
|
||||||
|
// match result {
|
||||||
|
// Ok(quotient) => divided_numbers.push(quotient),
|
||||||
|
// _ => continue
|
||||||
|
// }
|
||||||
|
// }
|
||||||
|
// if divided_numbers.is_empty() {
|
||||||
|
// ()
|
||||||
|
// }
|
||||||
|
// Ok(divided_numbers)
|
||||||
}
|
}
|
||||||
|
|
||||||
// Complete the function and return a value of the correct type so the test passes.
|
// Complete the function and return a value of the correct type so the test passes.
|
||||||
// Desired output: [Ok(1), Ok(11), Ok(1426), Ok(3)]
|
// Desired output: [Ok(1), Ok(11), Ok(1426), Ok(3)]
|
||||||
fn list_of_results() -> () {
|
fn list_of_results() -> Vec<Result<i32, DivisionError>> {
|
||||||
let numbers = vec![27, 297, 38502, 81];
|
let numbers = vec![27, 297, 38502, 81];
|
||||||
let division_results = numbers.into_iter().map(|n| divide(n, 27));
|
numbers.into_iter().map(|n| divide(n, 27)).collect()
|
||||||
|
// let mut divided_numbers: Vec<Result<i32, DivisionError>> = Vec::new();
|
||||||
|
// for result in division_results {
|
||||||
|
// match result {
|
||||||
|
// Ok(_) => divided_numbers.push(result),
|
||||||
|
// _ => continue
|
||||||
|
// }
|
||||||
|
// }
|
||||||
|
// division_results.for_each(|)
|
||||||
|
// divided_numbers
|
||||||
}
|
}
|
||||||
|
|
||||||
#[cfg(test)]
|
#[cfg(test)]
|
||||||
|
|||||||
@ -1,9 +1,15 @@
|
|||||||
// iterators4.rs
|
// iterators4.rs
|
||||||
// Execute `rustlings hint iterators4` or use the `hint` watch subcommand for a hint.
|
// Execute `rustlings hint iterators4` or use the `hint` watch subcommand for a hint.
|
||||||
|
|
||||||
// I AM NOT DONE
|
|
||||||
|
|
||||||
pub fn factorial(num: u64) -> u64 {
|
pub fn factorial(num: u64) -> u64 {
|
||||||
|
// let mut product: u64 = 1;
|
||||||
|
// for i in 2..num+1 {
|
||||||
|
// product *= i;
|
||||||
|
// }
|
||||||
|
// product
|
||||||
|
(2..num+1).into_iter().fold(1, |acc, x| x * acc)
|
||||||
|
|
||||||
// Complete this function to return the factorial of num
|
// Complete this function to return the factorial of num
|
||||||
// Do not use:
|
// Do not use:
|
||||||
// - return
|
// - return
|
||||||
|
|||||||
@ -10,7 +10,6 @@
|
|||||||
//
|
//
|
||||||
// Make the code compile and the tests pass.
|
// Make the code compile and the tests pass.
|
||||||
|
|
||||||
// I AM NOT DONE
|
|
||||||
|
|
||||||
use std::collections::HashMap;
|
use std::collections::HashMap;
|
||||||
|
|
||||||
@ -34,7 +33,8 @@ fn count_for(map: &HashMap<String, Progress>, value: Progress) -> usize {
|
|||||||
fn count_iterator(map: &HashMap<String, Progress>, value: Progress) -> usize {
|
fn count_iterator(map: &HashMap<String, Progress>, value: Progress) -> usize {
|
||||||
// map is a hashmap with String keys and Progress values.
|
// map is a hashmap with String keys and Progress values.
|
||||||
// map = { "variables1": Complete, "from_str": None, ... }
|
// map = { "variables1": Complete, "from_str": None, ... }
|
||||||
todo!();
|
let mut count = 0;
|
||||||
|
map.into_iter().filter_map(|(_, progress)| progress.eq(&value).then_some(value)).count()
|
||||||
}
|
}
|
||||||
|
|
||||||
fn count_collection_for(collection: &[HashMap<String, Progress>], value: Progress) -> usize {
|
fn count_collection_for(collection: &[HashMap<String, Progress>], value: Progress) -> usize {
|
||||||
@ -53,7 +53,8 @@ fn count_collection_iterator(collection: &[HashMap<String, Progress>], value: Pr
|
|||||||
// collection is a slice of hashmaps.
|
// collection is a slice of hashmaps.
|
||||||
// collection = [{ "variables1": Complete, "from_str": None, ... },
|
// collection = [{ "variables1": Complete, "from_str": None, ... },
|
||||||
// { "variables2": Complete, ... }, ... ]
|
// { "variables2": Complete, ... }, ... ]
|
||||||
todo!();
|
|
||||||
|
collection.into_iter().fold(0, |acc, map| acc + count_iterator(map, value))
|
||||||
}
|
}
|
||||||
|
|
||||||
#[cfg(test)]
|
#[cfg(test)]
|
||||||
|
|||||||
@ -7,9 +7,8 @@
|
|||||||
//
|
//
|
||||||
// Execute `rustlings hint lifetimes1` or use the `hint` watch subcommand for a hint.
|
// Execute `rustlings hint lifetimes1` or use the `hint` watch subcommand for a hint.
|
||||||
|
|
||||||
// I AM NOT DONE
|
|
||||||
|
|
||||||
fn longest(x: &str, y: &str) -> &str {
|
fn longest<'a>(x: &'a str, y: &'a str) -> &'a str {
|
||||||
if x.len() > y.len() {
|
if x.len() > y.len() {
|
||||||
x
|
x
|
||||||
} else {
|
} else {
|
||||||
|
|||||||
@ -6,8 +6,6 @@
|
|||||||
//
|
//
|
||||||
// Execute `rustlings hint lifetimes2` or use the `hint` watch subcommand for a hint.
|
// Execute `rustlings hint lifetimes2` or use the `hint` watch subcommand for a hint.
|
||||||
|
|
||||||
// I AM NOT DONE
|
|
||||||
|
|
||||||
fn longest<'a>(x: &'a str, y: &'a str) -> &'a str {
|
fn longest<'a>(x: &'a str, y: &'a str) -> &'a str {
|
||||||
if x.len() > y.len() {
|
if x.len() > y.len() {
|
||||||
x
|
x
|
||||||
@ -19,9 +17,9 @@ fn longest<'a>(x: &'a str, y: &'a str) -> &'a str {
|
|||||||
fn main() {
|
fn main() {
|
||||||
let string1 = String::from("long string is long");
|
let string1 = String::from("long string is long");
|
||||||
let result;
|
let result;
|
||||||
{
|
|
||||||
let string2 = String::from("xyz");
|
let string2 = String::from("xyz");
|
||||||
result = longest(string1.as_str(), string2.as_str());
|
result = longest(string1.as_str(), string2.as_str());
|
||||||
}
|
|
||||||
println!("The longest string is '{}'", result);
|
println!("The longest string is '{}'", result);
|
||||||
}
|
}
|
||||||
|
|||||||
@ -4,11 +4,10 @@
|
|||||||
//
|
//
|
||||||
// Execute `rustlings hint lifetimes3` or use the `hint` watch subcommand for a hint.
|
// Execute `rustlings hint lifetimes3` or use the `hint` watch subcommand for a hint.
|
||||||
|
|
||||||
// I AM NOT DONE
|
|
||||||
|
|
||||||
struct Book {
|
struct Book<'a> {
|
||||||
author: &str,
|
author: &'a str,
|
||||||
title: &str,
|
title: &'a str,
|
||||||
}
|
}
|
||||||
|
|
||||||
fn main() {
|
fn main() {
|
||||||
|
|||||||
@ -1,7 +1,6 @@
|
|||||||
// modules1.rs
|
// modules1.rs
|
||||||
// Execute `rustlings hint modules1` or use the `hint` watch subcommand for a hint.
|
// Execute `rustlings hint modules1` or use the `hint` watch subcommand for a hint.
|
||||||
|
|
||||||
// I AM NOT DONE
|
|
||||||
|
|
||||||
mod sausage_factory {
|
mod sausage_factory {
|
||||||
// Don't let anybody outside of this module see this!
|
// Don't let anybody outside of this module see this!
|
||||||
@ -9,7 +8,7 @@ mod sausage_factory {
|
|||||||
String::from("Ginger")
|
String::from("Ginger")
|
||||||
}
|
}
|
||||||
|
|
||||||
fn make_sausage() {
|
pub fn make_sausage() {
|
||||||
get_secret_recipe();
|
get_secret_recipe();
|
||||||
println!("sausage!");
|
println!("sausage!");
|
||||||
}
|
}
|
||||||
|
|||||||
@ -3,12 +3,11 @@
|
|||||||
// 'use' and 'as' keywords. Fix these 'use' statements to make the code compile.
|
// 'use' and 'as' keywords. Fix these 'use' statements to make the code compile.
|
||||||
// Execute `rustlings hint modules2` or use the `hint` watch subcommand for a hint.
|
// Execute `rustlings hint modules2` or use the `hint` watch subcommand for a hint.
|
||||||
|
|
||||||
// I AM NOT DONE
|
|
||||||
|
|
||||||
mod delicious_snacks {
|
pub mod delicious_snacks {
|
||||||
// TODO: Fix these use statements
|
// TODO: Fix these use statements
|
||||||
use self::fruits::PEAR as ???
|
pub use self::fruits::PEAR as fruit;
|
||||||
use self::veggies::CUCUMBER as ???
|
pub use self::veggies::CUCUMBER as veggie;
|
||||||
|
|
||||||
mod fruits {
|
mod fruits {
|
||||||
pub const PEAR: &'static str = "Pear";
|
pub const PEAR: &'static str = "Pear";
|
||||||
@ -21,6 +20,7 @@ mod delicious_snacks {
|
|||||||
}
|
}
|
||||||
}
|
}
|
||||||
|
|
||||||
|
|
||||||
fn main() {
|
fn main() {
|
||||||
println!(
|
println!(
|
||||||
"favorite snacks: {} and {}",
|
"favorite snacks: {} and {}",
|
||||||
|
|||||||
@ -5,10 +5,9 @@
|
|||||||
// from the std::time module. Bonus style points if you can do it with one line!
|
// from the std::time module. Bonus style points if you can do it with one line!
|
||||||
// Execute `rustlings hint modules3` or use the `hint` watch subcommand for a hint.
|
// Execute `rustlings hint modules3` or use the `hint` watch subcommand for a hint.
|
||||||
|
|
||||||
// I AM NOT DONE
|
|
||||||
|
|
||||||
// TODO: Complete this use statement
|
// TODO: Complete this use statement
|
||||||
use ???
|
use std::time::{SystemTime, UNIX_EPOCH};
|
||||||
|
|
||||||
fn main() {
|
fn main() {
|
||||||
match SystemTime::now().duration_since(UNIX_EPOCH) {
|
match SystemTime::now().duration_since(UNIX_EPOCH) {
|
||||||
|
|||||||
@ -1,12 +1,12 @@
|
|||||||
// move_semantics1.rs
|
// move_semantics1.rs
|
||||||
// Execute `rustlings hint move_semantics1` or use the `hint` watch subcommand for a hint.
|
// Execute `rustlings hint move_semantics1` or use the `hint` watch subcommand for a hint.
|
||||||
|
|
||||||
// I AM NOT DONE
|
|
||||||
|
|
||||||
fn main() {
|
fn main() {
|
||||||
let vec0 = Vec::new();
|
let vec0 = Vec::new();
|
||||||
|
|
||||||
let vec1 = fill_vec(vec0);
|
let mut vec1 = fill_vec(vec0);
|
||||||
|
|
||||||
println!("{} has length {} content `{:?}`", "vec1", vec1.len(), vec1);
|
println!("{} has length {} content `{:?}`", "vec1", vec1.len(), vec1);
|
||||||
|
|
||||||
|
|||||||
@ -2,12 +2,12 @@
|
|||||||
// Make me compile without changing line 13 or moving line 10!
|
// Make me compile without changing line 13 or moving line 10!
|
||||||
// Execute `rustlings hint move_semantics2` or use the `hint` watch subcommand for a hint.
|
// Execute `rustlings hint move_semantics2` or use the `hint` watch subcommand for a hint.
|
||||||
|
|
||||||
// I AM NOT DONE
|
|
||||||
|
|
||||||
fn main() {
|
fn main() {
|
||||||
let vec0 = Vec::new();
|
let vec0 = Vec::new();
|
||||||
|
|
||||||
let mut vec1 = fill_vec(vec0);
|
let mut vec1 = fill_vec(&vec0);
|
||||||
|
|
||||||
// Do not change the following line!
|
// Do not change the following line!
|
||||||
println!("{} has length {} content `{:?}`", "vec0", vec0.len(), vec0);
|
println!("{} has length {} content `{:?}`", "vec0", vec0.len(), vec0);
|
||||||
@ -17,8 +17,8 @@ fn main() {
|
|||||||
println!("{} has length {} content `{:?}`", "vec1", vec1.len(), vec1);
|
println!("{} has length {} content `{:?}`", "vec1", vec1.len(), vec1);
|
||||||
}
|
}
|
||||||
|
|
||||||
fn fill_vec(vec: Vec<i32>) -> Vec<i32> {
|
fn fill_vec(vec: &Vec<i32>) -> Vec<i32> {
|
||||||
let mut vec = vec;
|
let mut vec: Vec<i32> = vec.to_vec();
|
||||||
|
|
||||||
vec.push(22);
|
vec.push(22);
|
||||||
vec.push(44);
|
vec.push(44);
|
||||||
|
|||||||
@ -3,10 +3,10 @@
|
|||||||
// (no lines with multiple semicolons necessary!)
|
// (no lines with multiple semicolons necessary!)
|
||||||
// Execute `rustlings hint move_semantics3` or use the `hint` watch subcommand for a hint.
|
// Execute `rustlings hint move_semantics3` or use the `hint` watch subcommand for a hint.
|
||||||
|
|
||||||
// I AM NOT DONE
|
|
||||||
|
|
||||||
fn main() {
|
fn main() {
|
||||||
let vec0 = Vec::new();
|
let mut vec0 = Vec::new();
|
||||||
|
|
||||||
let mut vec1 = fill_vec(vec0);
|
let mut vec1 = fill_vec(vec0);
|
||||||
|
|
||||||
@ -17,7 +17,7 @@ fn main() {
|
|||||||
println!("{} has length {} content `{:?}`", "vec1", vec1.len(), vec1);
|
println!("{} has length {} content `{:?}`", "vec1", vec1.len(), vec1);
|
||||||
}
|
}
|
||||||
|
|
||||||
fn fill_vec(vec: Vec<i32>) -> Vec<i32> {
|
fn fill_vec(mut vec: Vec<i32>) -> Vec<i32> {
|
||||||
vec.push(22);
|
vec.push(22);
|
||||||
vec.push(44);
|
vec.push(44);
|
||||||
vec.push(66);
|
vec.push(66);
|
||||||
|
|||||||
@ -4,12 +4,11 @@
|
|||||||
// function.
|
// function.
|
||||||
// Execute `rustlings hint move_semantics4` or use the `hint` watch subcommand for a hint.
|
// Execute `rustlings hint move_semantics4` or use the `hint` watch subcommand for a hint.
|
||||||
|
|
||||||
// I AM NOT DONE
|
|
||||||
|
|
||||||
fn main() {
|
fn main() {
|
||||||
let vec0 = Vec::new();
|
// let vec0 = Vec::new();
|
||||||
|
|
||||||
let mut vec1 = fill_vec(vec0);
|
let mut vec1 = fill_vec();
|
||||||
|
|
||||||
println!("{} has length {} content `{:?}`", "vec1", vec1.len(), vec1);
|
println!("{} has length {} content `{:?}`", "vec1", vec1.len(), vec1);
|
||||||
|
|
||||||
@ -20,7 +19,7 @@ fn main() {
|
|||||||
|
|
||||||
// `fill_vec()` no longer takes `vec: Vec<i32>` as argument
|
// `fill_vec()` no longer takes `vec: Vec<i32>` as argument
|
||||||
fn fill_vec() -> Vec<i32> {
|
fn fill_vec() -> Vec<i32> {
|
||||||
let mut vec = vec;
|
let mut vec = Vec::new();
|
||||||
|
|
||||||
vec.push(22);
|
vec.push(22);
|
||||||
vec.push(44);
|
vec.push(44);
|
||||||
|
|||||||
@ -3,13 +3,12 @@
|
|||||||
// adding, changing or removing any of them.
|
// adding, changing or removing any of them.
|
||||||
// Execute `rustlings hint move_semantics5` or use the `hint` watch subcommand for a hint.
|
// Execute `rustlings hint move_semantics5` or use the `hint` watch subcommand for a hint.
|
||||||
|
|
||||||
// I AM NOT DONE
|
|
||||||
|
|
||||||
fn main() {
|
fn main() {
|
||||||
let mut x = 100;
|
let mut x = 100;
|
||||||
let y = &mut x;
|
let y = &mut x;
|
||||||
let z = &mut x;
|
|
||||||
*y += 100;
|
*y += 100;
|
||||||
|
let z = &mut x;
|
||||||
*z += 1000;
|
*z += 1000;
|
||||||
assert_eq!(x, 1200);
|
assert_eq!(x, 1200);
|
||||||
}
|
}
|
||||||
|
|||||||
@ -2,24 +2,24 @@
|
|||||||
// Execute `rustlings hint move_semantics6` or use the `hint` watch subcommand for a hint.
|
// Execute `rustlings hint move_semantics6` or use the `hint` watch subcommand for a hint.
|
||||||
// You can't change anything except adding or removing references.
|
// You can't change anything except adding or removing references.
|
||||||
|
|
||||||
// I AM NOT DONE
|
|
||||||
|
|
||||||
fn main() {
|
fn main() {
|
||||||
let data = "Rust is great!".to_string();
|
let data = "Rust is great!".to_string();
|
||||||
|
|
||||||
get_char(data);
|
get_char(&data);
|
||||||
|
|
||||||
string_uppercase(&data);
|
string_uppercase(data);
|
||||||
}
|
}
|
||||||
|
|
||||||
// Should not take ownership
|
// Should not take ownership
|
||||||
fn get_char(data: String) -> char {
|
fn get_char(data: &String) -> char {
|
||||||
data.chars().last().unwrap()
|
data.to_string().chars().last().unwrap()
|
||||||
}
|
}
|
||||||
|
|
||||||
// Should take ownership
|
// Should take ownership
|
||||||
fn string_uppercase(mut data: &String) {
|
fn string_uppercase(mut data: String) {
|
||||||
data = &data.to_uppercase();
|
data = data.to_uppercase();
|
||||||
|
|
||||||
println!("{}", data);
|
println!("{}", data);
|
||||||
}
|
}
|
||||||
|
|||||||
@ -1,7 +1,6 @@
|
|||||||
// options1.rs
|
// options1.rs
|
||||||
// Execute `rustlings hint options1` or use the `hint` watch subcommand for a hint.
|
// Execute `rustlings hint options1` or use the `hint` watch subcommand for a hint.
|
||||||
|
|
||||||
// I AM NOT DONE
|
|
||||||
|
|
||||||
// This function returns how much icecream there is left in the fridge.
|
// This function returns how much icecream there is left in the fridge.
|
||||||
// If it's before 10PM, there's 5 pieces left. At 10PM, someone eats them
|
// If it's before 10PM, there's 5 pieces left. At 10PM, someone eats them
|
||||||
@ -10,7 +9,13 @@ fn maybe_icecream(time_of_day: u16) -> Option<u16> {
|
|||||||
// We use the 24-hour system here, so 10PM is a value of 22 and 12AM is a value of 0
|
// We use the 24-hour system here, so 10PM is a value of 22 and 12AM is a value of 0
|
||||||
// The Option output should gracefully handle cases where time_of_day > 23.
|
// The Option output should gracefully handle cases where time_of_day > 23.
|
||||||
// TODO: Complete the function body - remember to return an Option!
|
// TODO: Complete the function body - remember to return an Option!
|
||||||
???
|
if time_of_day < 22 {
|
||||||
|
Some(5)
|
||||||
|
} else if time_of_day > 23 {
|
||||||
|
None
|
||||||
|
} else {
|
||||||
|
Some(0)
|
||||||
|
}
|
||||||
}
|
}
|
||||||
|
|
||||||
#[cfg(test)]
|
#[cfg(test)]
|
||||||
@ -30,6 +35,6 @@ mod tests {
|
|||||||
fn raw_value() {
|
fn raw_value() {
|
||||||
// TODO: Fix this test. How do you get at the value contained in the Option?
|
// TODO: Fix this test. How do you get at the value contained in the Option?
|
||||||
let icecreams = maybe_icecream(12);
|
let icecreams = maybe_icecream(12);
|
||||||
assert_eq!(icecreams, 5);
|
assert_eq!(icecreams.unwrap(), 5);
|
||||||
}
|
}
|
||||||
}
|
}
|
||||||
|
|||||||
@ -1,7 +1,6 @@
|
|||||||
// options2.rs
|
// options2.rs
|
||||||
// Execute `rustlings hint options2` or use the `hint` watch subcommand for a hint.
|
// Execute `rustlings hint options2` or use the `hint` watch subcommand for a hint.
|
||||||
|
|
||||||
// I AM NOT DONE
|
|
||||||
|
|
||||||
#[cfg(test)]
|
#[cfg(test)]
|
||||||
mod tests {
|
mod tests {
|
||||||
@ -11,7 +10,7 @@ mod tests {
|
|||||||
let optional_target = Some(target);
|
let optional_target = Some(target);
|
||||||
|
|
||||||
// TODO: Make this an if let statement whose value is "Some" type
|
// TODO: Make this an if let statement whose value is "Some" type
|
||||||
word = optional_target {
|
if let Some(word) = optional_target {
|
||||||
assert_eq!(word, target);
|
assert_eq!(word, target);
|
||||||
}
|
}
|
||||||
}
|
}
|
||||||
@ -26,7 +25,7 @@ mod tests {
|
|||||||
|
|
||||||
// TODO: make this a while let statement - remember that vector.pop also adds another layer of Option<T>
|
// TODO: make this a while let statement - remember that vector.pop also adds another layer of Option<T>
|
||||||
// You can stack `Option<T>`'s into while let and if let
|
// You can stack `Option<T>`'s into while let and if let
|
||||||
integer = optional_integers.pop() {
|
while let Some(Some(integer)) = optional_integers.pop() {
|
||||||
assert_eq!(integer, range);
|
assert_eq!(integer, range);
|
||||||
range -= 1;
|
range -= 1;
|
||||||
}
|
}
|
||||||
|
|||||||
@ -1,7 +1,6 @@
|
|||||||
// options3.rs
|
// options3.rs
|
||||||
// Execute `rustlings hint options3` or use the `hint` watch subcommand for a hint.
|
// Execute `rustlings hint options3` or use the `hint` watch subcommand for a hint.
|
||||||
|
|
||||||
// I AM NOT DONE
|
|
||||||
|
|
||||||
struct Point {
|
struct Point {
|
||||||
x: i32,
|
x: i32,
|
||||||
@ -11,7 +10,7 @@ struct Point {
|
|||||||
fn main() {
|
fn main() {
|
||||||
let y: Option<Point> = Some(Point { x: 100, y: 200 });
|
let y: Option<Point> = Some(Point { x: 100, y: 200 });
|
||||||
|
|
||||||
match y {
|
match &y {
|
||||||
Some(p) => println!("Co-ordinates are {},{} ", p.x, p.y),
|
Some(p) => println!("Co-ordinates are {},{} ", p.x, p.y),
|
||||||
_ => println!("no match"),
|
_ => println!("no match"),
|
||||||
}
|
}
|
||||||
|
|||||||
@ -2,7 +2,7 @@
|
|||||||
// Fill in the rest of the line that has code missing!
|
// Fill in the rest of the line that has code missing!
|
||||||
// No hints, there's no tricks, just get used to typing these :)
|
// No hints, there's no tricks, just get used to typing these :)
|
||||||
|
|
||||||
// I AM NOT DONE
|
|
||||||
|
|
||||||
fn main() {
|
fn main() {
|
||||||
// Booleans (`bool`)
|
// Booleans (`bool`)
|
||||||
@ -12,7 +12,7 @@ fn main() {
|
|||||||
println!("Good morning!");
|
println!("Good morning!");
|
||||||
}
|
}
|
||||||
|
|
||||||
let // Finish the rest of this line like the example! Or make it be false!
|
let is_evening = !is_morning;
|
||||||
if is_evening {
|
if is_evening {
|
||||||
println!("Good evening!");
|
println!("Good evening!");
|
||||||
}
|
}
|
||||||
|
|||||||
@ -2,7 +2,7 @@
|
|||||||
// Fill in the rest of the line that has code missing!
|
// Fill in the rest of the line that has code missing!
|
||||||
// No hints, there's no tricks, just get used to typing these :)
|
// No hints, there's no tricks, just get used to typing these :)
|
||||||
|
|
||||||
// I AM NOT DONE
|
|
||||||
|
|
||||||
fn main() {
|
fn main() {
|
||||||
// Characters (`char`)
|
// Characters (`char`)
|
||||||
@ -18,7 +18,7 @@ fn main() {
|
|||||||
println!("Neither alphabetic nor numeric!");
|
println!("Neither alphabetic nor numeric!");
|
||||||
}
|
}
|
||||||
|
|
||||||
let // Finish this line like the example! What's your favorite character?
|
let your_character = '&';
|
||||||
// Try a letter, try a number, try a special character, try a character
|
// Try a letter, try a number, try a special character, try a character
|
||||||
// from a different language than your own, try an emoji!
|
// from a different language than your own, try an emoji!
|
||||||
if your_character.is_alphabetic() {
|
if your_character.is_alphabetic() {
|
||||||
|
|||||||
@ -2,10 +2,10 @@
|
|||||||
// Create an array with at least 100 elements in it where the ??? is.
|
// Create an array with at least 100 elements in it where the ??? is.
|
||||||
// Execute `rustlings hint primitive_types3` or use the `hint` watch subcommand for a hint.
|
// Execute `rustlings hint primitive_types3` or use the `hint` watch subcommand for a hint.
|
||||||
|
|
||||||
// I AM NOT DONE
|
|
||||||
|
|
||||||
fn main() {
|
fn main() {
|
||||||
let a = ???
|
let a = [1..101];
|
||||||
|
|
||||||
if a.len() >= 100 {
|
if a.len() >= 100 {
|
||||||
println!("Wow, that's a big array!");
|
println!("Wow, that's a big array!");
|
||||||
|
|||||||
@ -2,13 +2,13 @@
|
|||||||
// Get a slice out of Array a where the ??? is so that the test passes.
|
// Get a slice out of Array a where the ??? is so that the test passes.
|
||||||
// Execute `rustlings hint primitive_types4` or use the `hint` watch subcommand for a hint.
|
// Execute `rustlings hint primitive_types4` or use the `hint` watch subcommand for a hint.
|
||||||
|
|
||||||
// I AM NOT DONE
|
|
||||||
|
|
||||||
#[test]
|
#[test]
|
||||||
fn slice_out_of_array() {
|
fn slice_out_of_array() {
|
||||||
let a = [1, 2, 3, 4, 5];
|
let a = [1, 2, 3, 4, 5];
|
||||||
|
|
||||||
let nice_slice = ???
|
let nice_slice = &a[1..4];
|
||||||
|
|
||||||
assert_eq!([2, 3, 4], nice_slice)
|
assert_eq!([2, 3, 4], nice_slice)
|
||||||
}
|
}
|
||||||
|
|||||||
@ -2,11 +2,11 @@
|
|||||||
// Destructure the `cat` tuple so that the println will work.
|
// Destructure the `cat` tuple so that the println will work.
|
||||||
// Execute `rustlings hint primitive_types5` or use the `hint` watch subcommand for a hint.
|
// Execute `rustlings hint primitive_types5` or use the `hint` watch subcommand for a hint.
|
||||||
|
|
||||||
// I AM NOT DONE
|
|
||||||
|
|
||||||
fn main() {
|
fn main() {
|
||||||
let cat = ("Furry McFurson", 3.5);
|
let cat = ("Furry McFurson", 3.5);
|
||||||
let /* your pattern here */ = cat;
|
let (name, age) = cat;
|
||||||
|
|
||||||
println!("{} is {} years old.", name, age);
|
println!("{} is {} years old.", name, age);
|
||||||
}
|
}
|
||||||
|
|||||||
@ -3,13 +3,13 @@
|
|||||||
// You can put the expression for the second element where ??? is so that the test passes.
|
// You can put the expression for the second element where ??? is so that the test passes.
|
||||||
// Execute `rustlings hint primitive_types6` or use the `hint` watch subcommand for a hint.
|
// Execute `rustlings hint primitive_types6` or use the `hint` watch subcommand for a hint.
|
||||||
|
|
||||||
// I AM NOT DONE
|
|
||||||
|
|
||||||
#[test]
|
#[test]
|
||||||
fn indexing_tuple() {
|
fn indexing_tuple() {
|
||||||
let numbers = (1, 2, 3);
|
let numbers = (1, 2, 3);
|
||||||
// Replace below ??? with the tuple indexing syntax.
|
// Replace below ??? with the tuple indexing syntax.
|
||||||
let second = ???;
|
let second = numbers.1;
|
||||||
|
|
||||||
assert_eq!(2, second,
|
assert_eq!(2, second,
|
||||||
"This is not the 2nd number in the tuple!")
|
"This is not the 2nd number in the tuple!")
|
||||||
|
|||||||
@ -10,8 +10,14 @@
|
|||||||
// Write a function that calculates the price of an order of apples given
|
// Write a function that calculates the price of an order of apples given
|
||||||
// the quantity bought. No hints this time!
|
// the quantity bought. No hints this time!
|
||||||
|
|
||||||
// I AM NOT DONE
|
|
||||||
|
|
||||||
|
|
||||||
|
fn calculate_price_of_apples(num_apples_bought:i32) -> i32 {
|
||||||
|
let mut price: i32;
|
||||||
|
if num_apples_bought > 40 {price = 1;}
|
||||||
|
else {price = 2;}
|
||||||
|
num_apples_bought * price
|
||||||
|
}
|
||||||
// Put your function here!
|
// Put your function here!
|
||||||
// fn calculate_price_of_apples {
|
// fn calculate_price_of_apples {
|
||||||
|
|
||||||
|
|||||||
@ -18,7 +18,6 @@
|
|||||||
// - The output element is going to be a Vector of strings.
|
// - The output element is going to be a Vector of strings.
|
||||||
// No hints this time!
|
// No hints this time!
|
||||||
|
|
||||||
// I AM NOT DONE
|
|
||||||
|
|
||||||
pub enum Command {
|
pub enum Command {
|
||||||
Uppercase,
|
Uppercase,
|
||||||
@ -30,11 +29,16 @@ mod my_module {
|
|||||||
use super::Command;
|
use super::Command;
|
||||||
|
|
||||||
// TODO: Complete the function signature!
|
// TODO: Complete the function signature!
|
||||||
pub fn transformer(input: ???) -> ??? {
|
pub fn transformer(input: Vec<(String, Command)>) -> Vec<String> {
|
||||||
// TODO: Complete the output declaration!
|
// TODO: Complete the output declaration!
|
||||||
let mut output: ??? = vec![];
|
let mut output = vec![];
|
||||||
for (string, command) in input.iter() {
|
for (string, command) in input.iter() {
|
||||||
// TODO: Complete the function body. You can do it!
|
match command {
|
||||||
|
Command::Uppercase => output.push(string.to_uppercase().to_string()),
|
||||||
|
Command::Trim => output.push(string.trim().to_string()),
|
||||||
|
Command::Append(n) => output.push(
|
||||||
|
string.to_string() + &"bar".repeat(*n)),
|
||||||
|
}
|
||||||
}
|
}
|
||||||
output
|
output
|
||||||
}
|
}
|
||||||
@ -43,7 +47,7 @@ mod my_module {
|
|||||||
#[cfg(test)]
|
#[cfg(test)]
|
||||||
mod tests {
|
mod tests {
|
||||||
// TODO: What do we need to import to have `transformer` in scope?
|
// TODO: What do we need to import to have `transformer` in scope?
|
||||||
use ???;
|
use super::my_module::transformer;
|
||||||
use super::Command;
|
use super::Command;
|
||||||
|
|
||||||
#[test]
|
#[test]
|
||||||
|
|||||||
@ -14,21 +14,28 @@
|
|||||||
|
|
||||||
// Execute `rustlings hint quiz3` or use the `hint` watch subcommand for a hint.
|
// Execute `rustlings hint quiz3` or use the `hint` watch subcommand for a hint.
|
||||||
|
|
||||||
// I AM NOT DONE
|
use std::fmt::Display;
|
||||||
|
|
||||||
pub struct ReportCard {
|
// pub enum Grade {
|
||||||
pub grade: f32,
|
// letter_grade: String,
|
||||||
|
// number_grade: u8,
|
||||||
|
// }
|
||||||
|
|
||||||
|
pub struct ReportCard<G: Display> {
|
||||||
|
pub grade: G,
|
||||||
pub student_name: String,
|
pub student_name: String,
|
||||||
pub student_age: u8,
|
pub student_age: u8,
|
||||||
}
|
}
|
||||||
|
|
||||||
impl ReportCard {
|
impl <G: Display> ReportCard <G> {
|
||||||
pub fn print(&self) -> String {
|
pub fn print(&self) -> String {
|
||||||
format!("{} ({}) - achieved a grade of {}",
|
format!("{} ({}) - achieved a grade of {}",
|
||||||
&self.student_name, &self.student_age, &self.grade)
|
&self.student_name, &self.student_age, &self.grade)
|
||||||
}
|
}
|
||||||
}
|
}
|
||||||
|
|
||||||
|
|
||||||
|
|
||||||
#[cfg(test)]
|
#[cfg(test)]
|
||||||
mod tests {
|
mod tests {
|
||||||
use super::*;
|
use super::*;
|
||||||
@ -50,7 +57,7 @@ mod tests {
|
|||||||
fn generate_alphabetic_report_card() {
|
fn generate_alphabetic_report_card() {
|
||||||
// TODO: Make sure to change the grade here after you finish the exercise.
|
// TODO: Make sure to change the grade here after you finish the exercise.
|
||||||
let report_card = ReportCard {
|
let report_card = ReportCard {
|
||||||
grade: 2.1,
|
grade: "A+".to_string(),
|
||||||
student_name: "Gary Plotter".to_string(),
|
student_name: "Gary Plotter".to_string(),
|
||||||
student_age: 11,
|
student_age: 11,
|
||||||
};
|
};
|
||||||
|
|||||||
@ -2,7 +2,6 @@
|
|||||||
// Make me compile without changing the function signature!
|
// Make me compile without changing the function signature!
|
||||||
// Execute `rustlings hint strings1` or use the `hint` watch subcommand for a hint.
|
// Execute `rustlings hint strings1` or use the `hint` watch subcommand for a hint.
|
||||||
|
|
||||||
// I AM NOT DONE
|
|
||||||
|
|
||||||
fn main() {
|
fn main() {
|
||||||
let answer = current_favorite_color();
|
let answer = current_favorite_color();
|
||||||
@ -10,5 +9,5 @@ fn main() {
|
|||||||
}
|
}
|
||||||
|
|
||||||
fn current_favorite_color() -> String {
|
fn current_favorite_color() -> String {
|
||||||
"blue"
|
"blue".to_string()
|
||||||
}
|
}
|
||||||
|
|||||||
@ -2,11 +2,10 @@
|
|||||||
// Make me compile without changing the function signature!
|
// Make me compile without changing the function signature!
|
||||||
// Execute `rustlings hint strings2` or use the `hint` watch subcommand for a hint.
|
// Execute `rustlings hint strings2` or use the `hint` watch subcommand for a hint.
|
||||||
|
|
||||||
// I AM NOT DONE
|
|
||||||
|
|
||||||
fn main() {
|
fn main() {
|
||||||
let word = String::from("green"); // Try not changing this line :)
|
let word = String::from("green"); // Try not changing this line :)
|
||||||
if is_a_color_word(word) {
|
if is_a_color_word(&word) {
|
||||||
println!("That is a color word I know!");
|
println!("That is a color word I know!");
|
||||||
} else {
|
} else {
|
||||||
println!("That is not a color word I know.");
|
println!("That is not a color word I know.");
|
||||||
|
|||||||
@ -1,21 +1,22 @@
|
|||||||
// strings3.rs
|
// strings3.rs
|
||||||
// Execute `rustlings hint strings3` or use the `hint` watch subcommand for a hint.
|
// Execute `rustlings hint strings3` or use the `hint` watch subcommand for a hint.
|
||||||
|
|
||||||
// I AM NOT DONE
|
|
||||||
|
|
||||||
fn trim_me(input: &str) -> String {
|
fn trim_me(input: &str) -> String {
|
||||||
// TODO: Remove whitespace from both ends of a string!
|
// TODO: Remove whitespace from both ends of a string!
|
||||||
???
|
input.trim().to_string()
|
||||||
}
|
}
|
||||||
|
|
||||||
fn compose_me(input: &str) -> String {
|
fn compose_me(input: &str) -> String {
|
||||||
// TODO: Add " world!" to the string! There's multiple ways to do this!
|
// TODO: Add " world!" to the string! There's multiple ways to do this!
|
||||||
???
|
let mut composed_string= String::from(input);
|
||||||
|
composed_string.push_str(" world!");
|
||||||
|
composed_string
|
||||||
}
|
}
|
||||||
|
|
||||||
fn replace_me(input: &str) -> String {
|
fn replace_me(input: &str) -> String {
|
||||||
// TODO: Replace "cars" in the string with "balloons"!
|
// TODO: Replace "cars" in the string with "balloons"!
|
||||||
???
|
input.replace("cars", "balloons").to_string()
|
||||||
}
|
}
|
||||||
|
|
||||||
#[cfg(test)]
|
#[cfg(test)]
|
||||||
|
|||||||
@ -6,7 +6,6 @@
|
|||||||
// before the parentheses on each line. If you're right, it will compile!
|
// before the parentheses on each line. If you're right, it will compile!
|
||||||
// No hints this time!
|
// No hints this time!
|
||||||
|
|
||||||
// I AM NOT DONE
|
|
||||||
|
|
||||||
fn string_slice(arg: &str) {
|
fn string_slice(arg: &str) {
|
||||||
println!("{}", arg);
|
println!("{}", arg);
|
||||||
@ -16,14 +15,14 @@ fn string(arg: String) {
|
|||||||
}
|
}
|
||||||
|
|
||||||
fn main() {
|
fn main() {
|
||||||
???("blue");
|
string_slice("blue");
|
||||||
???("red".to_string());
|
string("red".to_string());
|
||||||
???(String::from("hi"));
|
string(String::from("hi"));
|
||||||
???("rust is fun!".to_owned());
|
string("rust is fun!".to_owned());
|
||||||
???("nice weather".into());
|
string_slice("nice weather".into());
|
||||||
???(format!("Interpolation {}", "Station"));
|
string(format!("Interpolation {}", "Station"));
|
||||||
???(&String::from("abc")[0..1]);
|
string_slice(&String::from("abc")[0..1]);
|
||||||
???(" hello there ".trim());
|
string_slice(" hello there ".trim());
|
||||||
???("Happy Monday!".to_string().replace("Mon", "Tues"));
|
string("Happy Monday!".to_string().replace("Mon", "Tues"));
|
||||||
???("mY sHiFt KeY iS sTiCkY".to_lowercase());
|
string("mY sHiFt KeY iS sTiCkY".to_lowercase());
|
||||||
}
|
}
|
||||||
|
|||||||
@ -2,13 +2,20 @@
|
|||||||
// Address all the TODOs to make the tests pass!
|
// Address all the TODOs to make the tests pass!
|
||||||
// Execute `rustlings hint structs1` or use the `hint` watch subcommand for a hint.
|
// Execute `rustlings hint structs1` or use the `hint` watch subcommand for a hint.
|
||||||
|
|
||||||
// I AM NOT DONE
|
|
||||||
|
|
||||||
struct ColorClassicStruct {
|
struct ColorClassicStruct {
|
||||||
// TODO: Something goes here
|
red:usize,
|
||||||
|
green:usize,
|
||||||
|
blue:usize,
|
||||||
}
|
}
|
||||||
|
|
||||||
struct ColorTupleStruct(/* TODO: Something goes here */);
|
impl ColorClassicStruct {
|
||||||
|
fn new(red:usize, green:usize, blue:usize) -> ColorClassicStruct {
|
||||||
|
ColorClassicStruct { red: (red), green: (green), blue: (blue) }
|
||||||
|
}
|
||||||
|
}
|
||||||
|
struct ColorTupleStruct(i32, i32, i32);
|
||||||
|
|
||||||
#[derive(Debug)]
|
#[derive(Debug)]
|
||||||
struct UnitLikeStruct;
|
struct UnitLikeStruct;
|
||||||
@ -20,7 +27,7 @@ mod tests {
|
|||||||
#[test]
|
#[test]
|
||||||
fn classic_c_structs() {
|
fn classic_c_structs() {
|
||||||
// TODO: Instantiate a classic c struct!
|
// TODO: Instantiate a classic c struct!
|
||||||
// let green =
|
let green = ColorClassicStruct::new(0,255,0);
|
||||||
|
|
||||||
assert_eq!(green.red, 0);
|
assert_eq!(green.red, 0);
|
||||||
assert_eq!(green.green, 255);
|
assert_eq!(green.green, 255);
|
||||||
@ -30,7 +37,7 @@ mod tests {
|
|||||||
#[test]
|
#[test]
|
||||||
fn tuple_structs() {
|
fn tuple_structs() {
|
||||||
// TODO: Instantiate a tuple struct!
|
// TODO: Instantiate a tuple struct!
|
||||||
// let green =
|
let green = (0, 255, 0);
|
||||||
|
|
||||||
assert_eq!(green.0, 0);
|
assert_eq!(green.0, 0);
|
||||||
assert_eq!(green.1, 255);
|
assert_eq!(green.1, 255);
|
||||||
@ -40,7 +47,7 @@ mod tests {
|
|||||||
#[test]
|
#[test]
|
||||||
fn unit_structs() {
|
fn unit_structs() {
|
||||||
// TODO: Instantiate a unit-like struct!
|
// TODO: Instantiate a unit-like struct!
|
||||||
// let unit_like_struct =
|
let unit_like_struct = UnitLikeStruct;
|
||||||
let message = format!("{:?}s are fun!", unit_like_struct);
|
let message = format!("{:?}s are fun!", unit_like_struct);
|
||||||
|
|
||||||
assert_eq!(message, "UnitLikeStructs are fun!");
|
assert_eq!(message, "UnitLikeStructs are fun!");
|
||||||
|
|||||||
@ -2,7 +2,7 @@
|
|||||||
// Address all the TODOs to make the tests pass!
|
// Address all the TODOs to make the tests pass!
|
||||||
// Execute `rustlings hint structs2` or use the `hint` watch subcommand for a hint.
|
// Execute `rustlings hint structs2` or use the `hint` watch subcommand for a hint.
|
||||||
|
|
||||||
// I AM NOT DONE
|
|
||||||
|
|
||||||
#[derive(Debug)]
|
#[derive(Debug)]
|
||||||
struct Order {
|
struct Order {
|
||||||
@ -35,7 +35,11 @@ mod tests {
|
|||||||
fn your_order() {
|
fn your_order() {
|
||||||
let order_template = create_order_template();
|
let order_template = create_order_template();
|
||||||
// TODO: Create your own order using the update syntax and template above!
|
// TODO: Create your own order using the update syntax and template above!
|
||||||
// let your_order =
|
let mut your_order = create_order_template();
|
||||||
|
|
||||||
|
your_order.name = "Hacker in Rust".to_string();
|
||||||
|
your_order.count = 1;
|
||||||
|
|
||||||
assert_eq!(your_order.name, "Hacker in Rust");
|
assert_eq!(your_order.name, "Hacker in Rust");
|
||||||
assert_eq!(your_order.year, order_template.year);
|
assert_eq!(your_order.year, order_template.year);
|
||||||
assert_eq!(your_order.made_by_phone, order_template.made_by_phone);
|
assert_eq!(your_order.made_by_phone, order_template.made_by_phone);
|
||||||
|
|||||||
@ -4,7 +4,7 @@
|
|||||||
// Make the code compile and the tests pass!
|
// Make the code compile and the tests pass!
|
||||||
// Execute `rustlings hint structs3` or use the `hint` watch subcommand for a hint.
|
// Execute `rustlings hint structs3` or use the `hint` watch subcommand for a hint.
|
||||||
|
|
||||||
// I AM NOT DONE
|
|
||||||
|
|
||||||
#[derive(Debug)]
|
#[derive(Debug)]
|
||||||
struct Package {
|
struct Package {
|
||||||
@ -26,12 +26,12 @@ impl Package {
|
|||||||
}
|
}
|
||||||
}
|
}
|
||||||
|
|
||||||
fn is_international(&self) -> ??? {
|
fn is_international(&self) -> bool {
|
||||||
// Something goes here...
|
self.sender_country != self.recipient_country
|
||||||
}
|
}
|
||||||
|
|
||||||
fn get_fees(&self, cents_per_gram: i32) -> ??? {
|
fn get_fees(&self, cents_per_gram: i32) -> i32 {
|
||||||
// Something goes here...
|
self.weight_in_grams * cents_per_gram
|
||||||
}
|
}
|
||||||
}
|
}
|
||||||
|
|
||||||
|
|||||||
@ -7,12 +7,11 @@
|
|||||||
// pass! Make the test fail!
|
// pass! Make the test fail!
|
||||||
// Execute `rustlings hint tests1` or use the `hint` watch subcommand for a hint.
|
// Execute `rustlings hint tests1` or use the `hint` watch subcommand for a hint.
|
||||||
|
|
||||||
// I AM NOT DONE
|
|
||||||
|
|
||||||
#[cfg(test)]
|
#[cfg(test)]
|
||||||
mod tests {
|
mod tests {
|
||||||
#[test]
|
#[test]
|
||||||
fn you_can_assert() {
|
fn you_can_assert() {
|
||||||
assert!();
|
assert!(true);
|
||||||
}
|
}
|
||||||
}
|
}
|
||||||
|
|||||||
@ -3,12 +3,11 @@
|
|||||||
// pass! Make the test fail!
|
// pass! Make the test fail!
|
||||||
// Execute `rustlings hint tests2` or use the `hint` watch subcommand for a hint.
|
// Execute `rustlings hint tests2` or use the `hint` watch subcommand for a hint.
|
||||||
|
|
||||||
// I AM NOT DONE
|
|
||||||
|
|
||||||
#[cfg(test)]
|
#[cfg(test)]
|
||||||
mod tests {
|
mod tests {
|
||||||
#[test]
|
#[test]
|
||||||
fn you_can_assert_eq() {
|
fn you_can_assert_eq() {
|
||||||
assert_eq!();
|
assert_eq!(4,4);
|
||||||
}
|
}
|
||||||
}
|
}
|
||||||
|
|||||||
@ -4,7 +4,6 @@
|
|||||||
// we expect to get when we call `is_even(5)`.
|
// we expect to get when we call `is_even(5)`.
|
||||||
// Execute `rustlings hint tests3` or use the `hint` watch subcommand for a hint.
|
// Execute `rustlings hint tests3` or use the `hint` watch subcommand for a hint.
|
||||||
|
|
||||||
// I AM NOT DONE
|
|
||||||
|
|
||||||
pub fn is_even(num: i32) -> bool {
|
pub fn is_even(num: i32) -> bool {
|
||||||
num % 2 == 0
|
num % 2 == 0
|
||||||
@ -16,11 +15,11 @@ mod tests {
|
|||||||
|
|
||||||
#[test]
|
#[test]
|
||||||
fn is_true_when_even() {
|
fn is_true_when_even() {
|
||||||
assert!();
|
assert!(is_even(2));
|
||||||
}
|
}
|
||||||
|
|
||||||
#[test]
|
#[test]
|
||||||
fn is_false_when_odd() {
|
fn is_false_when_odd() {
|
||||||
assert!();
|
assert!(!is_even(5));
|
||||||
}
|
}
|
||||||
}
|
}
|
||||||
|
|||||||
@ -6,7 +6,6 @@
|
|||||||
// The program should wait until all the spawned threads have finished and
|
// The program should wait until all the spawned threads have finished and
|
||||||
// should collect their return values into a vector.
|
// should collect their return values into a vector.
|
||||||
|
|
||||||
// I AM NOT DONE
|
|
||||||
|
|
||||||
use std::thread;
|
use std::thread;
|
||||||
use std::time::{Duration, Instant};
|
use std::time::{Duration, Instant};
|
||||||
@ -24,7 +23,7 @@ fn main() {
|
|||||||
|
|
||||||
let mut results: Vec<u128> = vec![];
|
let mut results: Vec<u128> = vec![];
|
||||||
for handle in handles {
|
for handle in handles {
|
||||||
// TODO: a struct is returned from thread::spawn, can you use it?
|
results.push(handle.join().unwrap());
|
||||||
}
|
}
|
||||||
|
|
||||||
if results.len() != 10 {
|
if results.len() != 10 {
|
||||||
|
|||||||
@ -3,9 +3,8 @@
|
|||||||
// Building on the last exercise, we want all of the threads to complete their work but this time
|
// Building on the last exercise, we want all of the threads to complete their work but this time
|
||||||
// the spawned threads need to be in charge of updating a shared value: JobStatus.jobs_completed
|
// the spawned threads need to be in charge of updating a shared value: JobStatus.jobs_completed
|
||||||
|
|
||||||
// I AM NOT DONE
|
|
||||||
|
|
||||||
use std::sync::Arc;
|
use std::sync::{Arc, Mutex};
|
||||||
use std::thread;
|
use std::thread;
|
||||||
use std::time::Duration;
|
use std::time::Duration;
|
||||||
|
|
||||||
@ -14,14 +13,15 @@ struct JobStatus {
|
|||||||
}
|
}
|
||||||
|
|
||||||
fn main() {
|
fn main() {
|
||||||
let status = Arc::new(JobStatus { jobs_completed: 0 });
|
let status = Arc::new(Mutex::new(JobStatus { jobs_completed: 0 }));
|
||||||
let mut handles = vec![];
|
let mut handles = vec![];
|
||||||
for _ in 0..10 {
|
for _ in 0..10 {
|
||||||
let status_shared = Arc::clone(&status);
|
let status_shared = Arc::clone(&status);
|
||||||
let handle = thread::spawn(move || {
|
let handle = thread::spawn(move || {
|
||||||
thread::sleep(Duration::from_millis(250));
|
thread::sleep(Duration::from_millis(250));
|
||||||
// TODO: You must take an action before you update a shared value
|
// TODO: You must take an action before you update a shared value
|
||||||
status_shared.jobs_completed += 1;
|
status_shared.lock().unwrap().jobs_completed += 1;
|
||||||
|
|
||||||
});
|
});
|
||||||
handles.push(handle);
|
handles.push(handle);
|
||||||
}
|
}
|
||||||
@ -29,6 +29,6 @@ fn main() {
|
|||||||
handle.join().unwrap();
|
handle.join().unwrap();
|
||||||
// TODO: Print the value of the JobStatus.jobs_completed. Did you notice anything
|
// TODO: Print the value of the JobStatus.jobs_completed. Did you notice anything
|
||||||
// interesting in the output? Do you have to 'join' on all the handles?
|
// interesting in the output? Do you have to 'join' on all the handles?
|
||||||
println!("jobs completed {}", ???);
|
println!("jobs completed {}", status.lock().unwrap().jobs_completed);
|
||||||
}
|
}
|
||||||
}
|
}
|
||||||
|
|||||||
@ -9,14 +9,16 @@
|
|||||||
// implementing this trait.
|
// implementing this trait.
|
||||||
// Execute `rustlings hint traits1` or use the `hint` watch subcommand for a hint.
|
// Execute `rustlings hint traits1` or use the `hint` watch subcommand for a hint.
|
||||||
|
|
||||||
// I AM NOT DONE
|
|
||||||
|
|
||||||
trait AppendBar {
|
trait AppendBar {
|
||||||
fn append_bar(self) -> Self;
|
fn append_bar(self) -> Self;
|
||||||
}
|
}
|
||||||
|
|
||||||
impl AppendBar for String {
|
impl AppendBar for String {
|
||||||
// TODO: Implement `AppendBar` for type `String`.
|
fn append_bar(self) -> Self {
|
||||||
|
self + &"Bar".to_string()
|
||||||
|
}
|
||||||
}
|
}
|
||||||
|
|
||||||
fn main() {
|
fn main() {
|
||||||
|
|||||||
@ -11,13 +11,18 @@
|
|||||||
// you can do this!
|
// you can do this!
|
||||||
// Execute `rustlings hint traits2` or use the `hint` watch subcommand for a hint.
|
// Execute `rustlings hint traits2` or use the `hint` watch subcommand for a hint.
|
||||||
|
|
||||||
// I AM NOT DONE
|
|
||||||
|
|
||||||
trait AppendBar {
|
trait AppendBar {
|
||||||
fn append_bar(self) -> Self;
|
fn append_bar(self) -> Self;
|
||||||
}
|
}
|
||||||
|
|
||||||
// TODO: Implement trait `AppendBar` for a vector of strings.
|
impl AppendBar for Vec<String> {
|
||||||
|
fn append_bar(self) -> Self {
|
||||||
|
let mut new_vec: Vec<String> = self;
|
||||||
|
new_vec.push(String::from("Bar"));
|
||||||
|
new_vec
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
||||||
#[cfg(test)]
|
#[cfg(test)]
|
||||||
mod tests {
|
mod tests {
|
||||||
|
|||||||
@ -7,10 +7,11 @@
|
|||||||
// Consider what you can add to the Licensed trait.
|
// Consider what you can add to the Licensed trait.
|
||||||
// Execute `rustlings hint traits3` or use the `hint` watch subcommand for a hint.
|
// Execute `rustlings hint traits3` or use the `hint` watch subcommand for a hint.
|
||||||
|
|
||||||
// I AM NOT DONE
|
|
||||||
|
|
||||||
pub trait Licensed {
|
pub trait Licensed {
|
||||||
fn licensing_info(&self) -> String;
|
fn licensing_info(&self) -> String {
|
||||||
|
String::from("Some information")
|
||||||
|
}
|
||||||
}
|
}
|
||||||
|
|
||||||
struct SomeSoftware {
|
struct SomeSoftware {
|
||||||
|
|||||||
@ -4,7 +4,6 @@
|
|||||||
// Don't change any line other than the marked one.
|
// Don't change any line other than the marked one.
|
||||||
// Execute `rustlings hint traits4` or use the `hint` watch subcommand for a hint.
|
// Execute `rustlings hint traits4` or use the `hint` watch subcommand for a hint.
|
||||||
|
|
||||||
// I AM NOT DONE
|
|
||||||
|
|
||||||
pub trait Licensed {
|
pub trait Licensed {
|
||||||
fn licensing_info(&self) -> String {
|
fn licensing_info(&self) -> String {
|
||||||
@ -20,7 +19,17 @@ impl Licensed for SomeSoftware {}
|
|||||||
impl Licensed for OtherSoftware {}
|
impl Licensed for OtherSoftware {}
|
||||||
|
|
||||||
// YOU MAY ONLY CHANGE THE NEXT LINE
|
// YOU MAY ONLY CHANGE THE NEXT LINE
|
||||||
fn compare_license_types(software: ??, software_two: ??) -> bool {
|
// fn compare_license_types<T,S>(software: T, software_two: S) -> bool
|
||||||
|
// where
|
||||||
|
// T: Licensed,
|
||||||
|
// S: Licensed
|
||||||
|
// {software.licensing_info() == software_two.licensing_info()
|
||||||
|
// }
|
||||||
|
// fn compare_license_types(software: (impl Licensed), software_two: (impl Licensed)) -> bool
|
||||||
|
|
||||||
|
// {software.licensing_info() == software_two.licensing_info()
|
||||||
|
// }
|
||||||
|
fn compare_license_types<T: Licensed,S: Licensed>(software: T, software_two: S) -> bool {
|
||||||
software.licensing_info() == software_two.licensing_info()
|
software.licensing_info() == software_two.licensing_info()
|
||||||
}
|
}
|
||||||
|
|
||||||
|
|||||||
@ -4,7 +4,6 @@
|
|||||||
// Don't change any line other than the marked one.
|
// Don't change any line other than the marked one.
|
||||||
// Execute `rustlings hint traits5` or use the `hint` watch subcommand for a hint.
|
// Execute `rustlings hint traits5` or use the `hint` watch subcommand for a hint.
|
||||||
|
|
||||||
// I AM NOT DONE
|
|
||||||
|
|
||||||
pub trait SomeTrait {
|
pub trait SomeTrait {
|
||||||
fn some_function(&self) -> bool {
|
fn some_function(&self) -> bool {
|
||||||
@ -27,7 +26,7 @@ impl SomeTrait for OtherStruct {}
|
|||||||
impl OtherTrait for OtherStruct {}
|
impl OtherTrait for OtherStruct {}
|
||||||
|
|
||||||
// YOU MAY ONLY CHANGE THE NEXT LINE
|
// YOU MAY ONLY CHANGE THE NEXT LINE
|
||||||
fn some_func(item: ??) -> bool {
|
fn some_func<T:SomeTrait+OtherTrait>(item: T) -> bool {
|
||||||
item.some_function() && item.other_function()
|
item.some_function() && item.other_function()
|
||||||
}
|
}
|
||||||
|
|
||||||
|
|||||||
@ -2,9 +2,9 @@
|
|||||||
// Make me compile!
|
// Make me compile!
|
||||||
// Execute `rustlings hint variables1` or use the `hint` watch subcommand for a hint.
|
// Execute `rustlings hint variables1` or use the `hint` watch subcommand for a hint.
|
||||||
|
|
||||||
// I AM NOT DONE
|
|
||||||
|
|
||||||
fn main() {
|
fn main() {
|
||||||
x = 5;
|
let x = 5;
|
||||||
println!("x has the value {}", x);
|
println!("x has the value {}", x);
|
||||||
}
|
}
|
||||||
|
|||||||
@ -1,10 +1,10 @@
|
|||||||
// variables2.rs
|
// variables2.rs
|
||||||
// Execute `rustlings hint variables2` or use the `hint` watch subcommand for a hint.
|
// Execute `rustlings hint variables2` or use the `hint` watch subcommand for a hint.
|
||||||
|
|
||||||
// I AM NOT DONE
|
|
||||||
|
|
||||||
fn main() {
|
fn main() {
|
||||||
let x;
|
let x = 10;
|
||||||
if x == 10 {
|
if x == 10 {
|
||||||
println!("x is ten!");
|
println!("x is ten!");
|
||||||
} else {
|
} else {
|
||||||
|
|||||||
@ -1,9 +1,9 @@
|
|||||||
// variables3.rs
|
// variables3.rs
|
||||||
// Execute `rustlings hint variables3` or use the `hint` watch subcommand for a hint.
|
// Execute `rustlings hint variables3` or use the `hint` watch subcommand for a hint.
|
||||||
|
|
||||||
// I AM NOT DONE
|
|
||||||
|
|
||||||
fn main() {
|
fn main() {
|
||||||
let x: i32;
|
let x: i32 = 7;
|
||||||
println!("Number {}", x);
|
println!("Number {}", x);
|
||||||
}
|
}
|
||||||
|
|||||||
@ -1,10 +1,10 @@
|
|||||||
// variables4.rs
|
// variables4.rs
|
||||||
// Execute `rustlings hint variables4` or use the `hint` watch subcommand for a hint.
|
// Execute `rustlings hint variables4` or use the `hint` watch subcommand for a hint.
|
||||||
|
|
||||||
// I AM NOT DONE
|
|
||||||
|
|
||||||
fn main() {
|
fn main() {
|
||||||
let x = 3;
|
let mut x = 3;
|
||||||
println!("Number {}", x);
|
println!("Number {}", x);
|
||||||
x = 5; // don't change this line
|
x = 5; // don't change this line
|
||||||
println!("Number {}", x);
|
println!("Number {}", x);
|
||||||
|
|||||||
@ -1,11 +1,12 @@
|
|||||||
// variables5.rs
|
// variables5.rs
|
||||||
// Execute `rustlings hint variables5` or use the `hint` watch subcommand for a hint.
|
// Execute `rustlings hint variables5` or use the `hint` watch subcommand for a hint.
|
||||||
|
|
||||||
// I AM NOT DONE
|
|
||||||
|
|
||||||
fn main() {
|
fn main() {
|
||||||
let number = "T-H-R-E-E"; // don't change this line
|
let number = "T-H-R-E-E"; // don't change this line
|
||||||
println!("Spell a Number : {}", number);
|
println!("Spell a Number : {}", number);
|
||||||
number = 3; // don't rename this variable
|
{ let number: i32 = 3; // don't rename this variable
|
||||||
println!("Number plus two is : {}", number + 2);
|
println!("Number plus two is : {}", number + 2);
|
||||||
|
}
|
||||||
}
|
}
|
||||||
|
|||||||
@ -1,9 +1,8 @@
|
|||||||
// variables6.rs
|
// variables6.rs
|
||||||
// Execute `rustlings hint variables6` or use the `hint` watch subcommand for a hint.
|
// Execute `rustlings hint variables6` or use the `hint` watch subcommand for a hint.
|
||||||
|
|
||||||
// I AM NOT DONE
|
|
||||||
|
|
||||||
const NUMBER = 3;
|
const NUMBER: usize = 3;
|
||||||
fn main() {
|
fn main() {
|
||||||
println!("Number {}", NUMBER);
|
println!("Number {}", NUMBER);
|
||||||
}
|
}
|
||||||
|
|||||||
@ -4,11 +4,11 @@
|
|||||||
// Make me compile and pass the test!
|
// Make me compile and pass the test!
|
||||||
// Execute `rustlings hint vecs1` or use the `hint` watch subcommand for a hint.
|
// Execute `rustlings hint vecs1` or use the `hint` watch subcommand for a hint.
|
||||||
|
|
||||||
// I AM NOT DONE
|
|
||||||
|
|
||||||
fn array_and_vec() -> ([i32; 4], Vec<i32>) {
|
fn array_and_vec() -> ([i32; 4], Vec<i32>) {
|
||||||
let a = [10, 20, 30, 40]; // a plain array
|
let a = [10, 20, 30, 40]; // a plain array
|
||||||
let v = // TODO: declare your vector here with the macro for vectors
|
let v = vec!(a[0], a[1], a[2], a[3]); // TODO: declare your vector here with the macro for vectors
|
||||||
|
|
||||||
(a, v)
|
(a, v)
|
||||||
}
|
}
|
||||||
|
|||||||
@ -6,13 +6,13 @@
|
|||||||
//
|
//
|
||||||
// Execute `rustlings hint vecs2` or use the `hint` watch subcommand for a hint.
|
// Execute `rustlings hint vecs2` or use the `hint` watch subcommand for a hint.
|
||||||
|
|
||||||
// I AM NOT DONE
|
|
||||||
|
|
||||||
fn vec_loop(mut v: Vec<i32>) -> Vec<i32> {
|
fn vec_loop(mut v: Vec<i32>) -> Vec<i32> {
|
||||||
for element in v.iter_mut() {
|
for element in v.iter_mut() {
|
||||||
// TODO: Fill this up so that each element in the Vec `v` is
|
// TODO: Fill this up so that each element in the Vec `v` is
|
||||||
// multiplied by 2.
|
// multiplied by 2.
|
||||||
???
|
*element = *element * 2;
|
||||||
}
|
}
|
||||||
|
|
||||||
// At this point, `v` should be equal to [4, 8, 12, 16, 20].
|
// At this point, `v` should be equal to [4, 8, 12, 16, 20].
|
||||||
@ -23,7 +23,7 @@ fn vec_map(v: &Vec<i32>) -> Vec<i32> {
|
|||||||
v.iter().map(|element| {
|
v.iter().map(|element| {
|
||||||
// TODO: Do the same thing as above - but instead of mutating the
|
// TODO: Do the same thing as above - but instead of mutating the
|
||||||
// Vec, you can just return the new number!
|
// Vec, you can just return the new number!
|
||||||
???
|
*element * 2
|
||||||
}).collect()
|
}).collect()
|
||||||
}
|
}
|
||||||
|
|
||||||
|
|||||||
1
rustlings
Submodule
1
rustlings
Submodule
@ -0,0 +1 @@
|
|||||||
|
Subproject commit 7f1754ecc5690f31db4aff38eef2bf30e2aec525
|
||||||
Loading…
x
Reference in New Issue
Block a user