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https://github.com/rust-lang/rustlings.git
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🎉 complete quiz3
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@ -3,7 +3,7 @@
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// Execute `rustlings hint options1` or use the `hint` watch subcommand for a
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// hint.
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// I AM NOT DONE
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use core::time;
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// This function returns how much icecream there is left in the fridge.
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// If it's before 10PM, there's 5 pieces left. At 10PM, someone eats them
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@ -12,8 +12,11 @@ fn maybe_icecream(time_of_day: u16) -> Option<u16> {
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// We use the 24-hour system here, so 10PM is a value of 22 and 12AM is a
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// value of 0 The Option output should gracefully handle cases where
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// time_of_day > 23.
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// TODO: Complete the function body - remember to return an Option!
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???
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match time_of_day {
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0..=21 => Some(5),
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22..=24 => Some(0),
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_ => None,
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}
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}
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#[cfg(test)]
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@ -34,6 +37,6 @@ mod tests {
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// TODO: Fix this test. How do you get at the value contained in the
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// Option?
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let icecreams = maybe_icecream(12);
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assert_eq!(icecreams, 5);
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assert_eq!(icecreams.unwrap(), 5);
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}
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}
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@ -3,7 +3,6 @@
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// Execute `rustlings hint options2` or use the `hint` watch subcommand for a
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// hint.
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// I AM NOT DONE
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#[cfg(test)]
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mod tests {
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@ -12,8 +11,7 @@ mod tests {
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let target = "rustlings";
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let optional_target = Some(target);
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// TODO: Make this an if let statement whose value is "Some" type
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word = optional_target {
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if let Some(word) = optional_target {
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assert_eq!(word, target);
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}
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}
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@ -32,7 +30,7 @@ mod tests {
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// TODO: make this a while let statement - remember that vector.pop also
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// adds another layer of Option<T>. You can stack `Option<T>`s into
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// while let and if let.
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integer = optional_integers.pop() {
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while let Some(integer) = optional_integers.pop().flatten() {
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assert_eq!(integer, cursor);
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cursor -= 1;
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}
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@ -3,7 +3,6 @@
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// Execute `rustlings hint options3` or use the `hint` watch subcommand for a
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// hint.
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// I AM NOT DONE
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struct Point {
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x: i32,
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@ -14,7 +13,7 @@ fn main() {
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let y: Option<Point> = Some(Point { x: 100, y: 200 });
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match y {
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Some(p) => println!("Co-ordinates are {},{} ", p.x, p.y),
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Some(ref p) => println!("Co-ordinates are {},{} ", p.x, p.y),
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_ => panic!("no match!"),
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}
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y; // Fix without deleting this line.
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@ -9,14 +9,13 @@
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// Execute `rustlings hint errors1` or use the `hint` watch subcommand for a
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// hint.
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// I AM NOT DONE
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pub fn generate_nametag_text(name: String) -> Option<String> {
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pub fn generate_nametag_text(name: String) -> Result<String, String> {
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if name.is_empty() {
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// Empty names aren't allowed.
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None
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Err("`name` was empty; it must be nonempty.".into())
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} else {
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Some(format!("Hi! My name is {}", name))
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Ok(format!("Hi! My name is {}", name))
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}
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}
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@ -19,16 +19,19 @@
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// Execute `rustlings hint errors2` or use the `hint` watch subcommand for a
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// hint.
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// I AM NOT DONE
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use std::num::ParseIntError;
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pub fn total_cost(item_quantity: &str) -> Result<i32, ParseIntError> {
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let processing_fee = 1;
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let cost_per_item = 5;
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let qty = item_quantity.parse::<i32>();
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let qty = item_quantity.parse::<i32>()?;
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Ok(qty * cost_per_item + processing_fee)
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// match item_quantity.parse::<i32>(){
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// Ok(qty) => Ok(qty * cost_per_item + processing_fee),
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// Err(e) => Err(e)
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// }
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}
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#[cfg(test)]
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BIN
exercises/13_error_handling/errors3
Executable file
BIN
exercises/13_error_handling/errors3
Executable file
Binary file not shown.
@ -7,7 +7,6 @@
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// Execute `rustlings hint errors3` or use the `hint` watch subcommand for a
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// hint.
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// I AM NOT DONE
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use std::num::ParseIntError;
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@ -15,7 +14,7 @@ fn main() {
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let mut tokens = 100;
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let pretend_user_input = "8";
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let cost = total_cost(pretend_user_input)?;
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let cost = total_cost(pretend_user_input).unwrap();
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if cost > tokens {
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println!("You can't afford that many!");
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@ -3,8 +3,6 @@
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// Execute `rustlings hint errors4` or use the `hint` watch subcommand for a
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// hint.
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// I AM NOT DONE
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#[derive(PartialEq, Debug)]
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struct PositiveNonzeroInteger(u64);
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@ -17,7 +15,11 @@ enum CreationError {
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impl PositiveNonzeroInteger {
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fn new(value: i64) -> Result<PositiveNonzeroInteger, CreationError> {
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// Hmm... Why is this always returning an Ok value?
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Ok(PositiveNonzeroInteger(value as u64))
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match value {
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v if v <0 => Err(CreationError::Negative),
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0 => Err(CreationError::Zero),
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v => Ok(PositiveNonzeroInteger(value as u64))
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}
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}
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}
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@ -22,14 +22,13 @@
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// Execute `rustlings hint errors5` or use the `hint` watch subcommand for a
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// hint.
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// I AM NOT DONE
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use std::error;
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use std::fmt;
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use std::num::ParseIntError;
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// TODO: update the return type of `main()` to make this compile.
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fn main() -> Result<(), Box<dyn ???>> {
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fn main() -> Result<(), Box<dyn error::Error>> {
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let pretend_user_input = "42";
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let x: i64 = pretend_user_input.parse()?;
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println!("output={:?}", PositiveNonzeroInteger::new(x)?);
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@ -9,8 +9,6 @@
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// Execute `rustlings hint errors6` or use the `hint` watch subcommand for a
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// hint.
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// I AM NOT DONE
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use std::num::ParseIntError;
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// This is a custom error type that we will be using in `parse_pos_nonzero()`.
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@ -25,13 +23,15 @@ impl ParsePosNonzeroError {
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ParsePosNonzeroError::Creation(err)
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}
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// TODO: add another error conversion function here.
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// fn from_parseint...
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fn from_parseint(err: ParseIntError) -> ParsePosNonzeroError {
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ParsePosNonzeroError::ParseInt(err)
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}
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}
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fn parse_pos_nonzero(s: &str) -> Result<PositiveNonzeroInteger, ParsePosNonzeroError> {
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// TODO: change this to return an appropriate error instead of panicking
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// when `parse()` returns an error.
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let x: i64 = s.parse().unwrap();
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let x: i64 = s.parse().map_err(ParsePosNonzeroError::from_parseint)?;
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PositiveNonzeroInteger::new(x).map_err(ParsePosNonzeroError::from_creation)
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}
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@ -6,9 +6,8 @@
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// Execute `rustlings hint generics1` or use the `hint` watch subcommand for a
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// hint.
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// I AM NOT DONE
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fn main() {
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let mut shopping_list: Vec<?> = Vec::new();
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let mut shopping_list: Vec<&str> = Vec::new();
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shopping_list.push("milk");
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}
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@ -6,14 +6,13 @@
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// Execute `rustlings hint generics2` or use the `hint` watch subcommand for a
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// hint.
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// I AM NOT DONE
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struct Wrapper {
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value: u32,
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struct Wrapper<T> {
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value: T,
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}
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impl Wrapper {
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pub fn new(value: u32) -> Self {
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impl<T> Wrapper<T> {
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pub fn new(value: T) -> Self {
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Wrapper { value }
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}
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}
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@ -7,14 +7,15 @@
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// Execute `rustlings hint traits1` or use the `hint` watch subcommand for a
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// hint.
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// I AM NOT DONE
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trait AppendBar {
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fn append_bar(self) -> Self;
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}
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impl AppendBar for String {
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// TODO: Implement `AppendBar` for type `String`.
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fn append_bar(self) -> Self {
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self + "Bar"
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}
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}
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fn main() {
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@ -8,13 +8,18 @@
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//
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// Execute `rustlings hint traits2` or use the `hint` watch subcommand for a hint.
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// I AM NOT DONE
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trait AppendBar {
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fn append_bar(self) -> Self;
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}
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// TODO: Implement trait `AppendBar` for a vector of strings.
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impl AppendBar for Vec<String> {
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fn append_bar(mut self) -> Self {
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self.push("Bar".to_string());
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self
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}
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}
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#[cfg(test)]
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mod tests {
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@ -8,10 +8,11 @@
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// Execute `rustlings hint traits3` or use the `hint` watch subcommand for a
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// hint.
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// I AM NOT DONE
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pub trait Licensed {
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fn licensing_info(&self) -> String;
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fn licensing_info(&self) -> String{
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"Some information".to_string()
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}
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}
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struct SomeSoftware {
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@ -7,7 +7,6 @@
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// Execute `rustlings hint traits4` or use the `hint` watch subcommand for a
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// hint.
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// I AM NOT DONE
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pub trait Licensed {
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fn licensing_info(&self) -> String {
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@ -23,7 +22,7 @@ impl Licensed for SomeSoftware {}
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impl Licensed for OtherSoftware {}
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// YOU MAY ONLY CHANGE THE NEXT LINE
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fn compare_license_types(software: ??, software_two: ??) -> bool {
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fn compare_license_types(software: impl Licensed, software_two: impl Licensed) -> bool {
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software.licensing_info() == software_two.licensing_info()
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}
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@ -7,7 +7,6 @@
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// Execute `rustlings hint traits5` or use the `hint` watch subcommand for a
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// hint.
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// I AM NOT DONE
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pub trait SomeTrait {
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fn some_function(&self) -> bool {
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@ -30,7 +29,7 @@ impl SomeTrait for OtherStruct {}
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impl OtherTrait for OtherStruct {}
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// YOU MAY ONLY CHANGE THE NEXT LINE
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fn some_func(item: ??) -> bool {
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fn some_func(item: impl SomeTrait + OtherTrait) -> bool {
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item.some_function() && item.other_function()
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}
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@ -16,16 +16,20 @@
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//
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// Execute `rustlings hint quiz3` or use the `hint` watch subcommand for a hint.
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// I AM NOT DONE
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pub struct ReportCard {
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pub grade: f32,
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use std::fmt::Display;
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pub struct ReportCard<T> {
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pub grade: T,
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pub student_name: String,
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pub student_age: u8,
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}
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impl ReportCard {
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pub fn print(&self) -> String {
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impl<T> ReportCard<T> {
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pub fn print(&self) -> String
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where
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T: Display,
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{
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format!("{} ({}) - achieved a grade of {}",
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&self.student_name, &self.student_age, &self.grade)
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}
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@ -52,7 +56,7 @@ mod tests {
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fn generate_alphabetic_report_card() {
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// TODO: Make sure to change the grade here after you finish the exercise.
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let report_card = ReportCard {
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grade: 2.1,
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grade: "A+",
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student_name: "Gary Plotter".to_string(),
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student_age: 11,
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};
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