solved till smart pointers

.vscode/extensions.json

@@ -1,5 +0,0 @@
-{
-    "recommendations": [
-        "rust-lang.rust-analyzer"
-    ]
-}

exercises/README.md

@@ -1,5 +1,16 @@
+
 # Exercise to Book Chapter mapping
 
+| Exercise               | Book Chapter        |
+| ---------------------- | ------------------- |
+| threads                | §16.1-3             |
+| macros                 | §19.6               |
+| clippy                 | §21.4               |
+| conversions            | n/a                 |
+
+
+
+# Done
 | Exercise               | Book Chapter        |
 | ---------------------- | ------------------- |
 | variables              | §3.1                |
@@ -17,11 +28,7 @@
 | error_handling         | §9                  |
 | generics               | §10                 |
 | traits                 | §10.2               |
-| tests                  | §11.1               |
 | lifetimes              | §10.3               |
+| tests                  | §11.1               |
 | iterators              | §13.2-4             |
-| threads                | §16.1-3             |
 | smart_pointers         | §15, §16.3          |
-| macros                 | §19.6               |
-| clippy                 | §21.4               |
-| conversions            | n/a                 |

exercises/enums/enums1.rs

@@ -2,11 +2,12 @@
 //
 // No hints this time! ;)
 
-// I AM NOT DONE
-
 #[derive(Debug)]
 enum Message {
-    // TODO: define a few types of messages as used below
+    Echo,
+    Move,
+    ChangeColor,
+    Quit, // TODO: define a few types of messages as used below
 }
 
 fn main() {

exercises/enums/enums2.rs

@@ -3,11 +3,12 @@
 // Execute `rustlings hint enums2` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
 #[derive(Debug)]
 enum Message {
-    // TODO: define the different variants used below
+    Move { x: u32, y: u32 },
+    Echo(String),
+    ChangeColor(u8, u8, u8),
+    Quit, // TODO: define the different variants used below
 }
 
 impl Message {

exercises/enums/enums3.rs

@@ -5,10 +5,11 @@
 // Execute `rustlings hint enums3` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
 enum Message {
-    // TODO: implement the message variant types based on their usage below
+    ChangeColor(u8, u8, u8),
+    Echo(String),
+    Move(Point),
+    Quit, // TODO: implement the message variant types based on their usage below
 }
 
 struct Point {
@@ -41,6 +42,21 @@ impl State {
     }
 
     fn process(&mut self, message: Message) {
+        match message {
+            Message::ChangeColor(red, green, blue) => {
+                self.color.0 = red;
+                self.color.1 = green;
+                self.color.2 = blue;
+            }
+            Message::Echo(msg) => {
+                self.message = msg;
+            }
+            Message::Move(position) => {
+                self.position.x = position.x;
+                self.position.y = position.y;
+            }
+            Message::Quit => self.quit = true,
+        }
         // TODO: create a match expression to process the different message
         // variants
         // Remember: When passing a tuple as a function argument, you'll need

exercises/error_handling/README.md

@@ -5,7 +5,6 @@ Sometimes, when a function fails, it’s for a reason that you can easily interp
 For example, if you try to open a file and that operation fails because the file doesn’t exist, you might want to create the file instead of terminating the process.
 
 ## Further information
-
 - [Error Handling](https://doc.rust-lang.org/book/ch09-02-recoverable-errors-with-result.html)
 - [Generics](https://doc.rust-lang.org/book/ch10-01-syntax.html)
 - [Result](https://doc.rust-lang.org/rust-by-example/error/result.html)

exercises/error_handling/errors1.rs

@@ -9,14 +9,12 @@
 // Execute `rustlings hint errors1` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+pub fn generate_nametag_text(name: String) -> Result<String, String> {
-
-pub fn generate_nametag_text(name: String) -> Option<String> {
     if name.is_empty() {
         // Empty names aren't allowed.
-        None
+        Err(String::from("`name` was empty; it must be nonempty."))
     } else {
-        Some(format!("Hi! My name is {}", name))
+        Ok(format!("Hi! My name is {}", name))
     }
 }
 

exercises/error_handling/errors2.rs

@@ -1,26 +1,24 @@
 // errors2.rs
 //
-// Say we're writing a game where you can buy items with tokens. All items cost
+// INFO: Say we're writing a game where you can buy items with tokens. All items cost
 // 5 tokens, and whenever you purchase items there is a processing fee of 1
 // token. A player of the game will type in how many items they want to buy, and
 // the `total_cost` function will calculate the total cost of the tokens. Since
 // the player typed in the quantity, though, we get it as a string-- and they
 // might have typed anything, not just numbers!
 //
-// Right now, this function isn't handling the error case at all (and isn't
+// INFO: Right now, this function isn't handling the error case at all (and isn't
 // handling the success case properly either). What we want to do is: if we call
 // the `total_cost` function on a string that is not a number, that function
 // will return a `ParseIntError`, and in that case, we want to immediately
 // return that error from our function and not try to multiply and add.
 //
-// There are at least two ways to implement this that are both correct-- but one
+// TODO: There are at least two ways to implement this that are both correct-- but one
 // is a lot shorter!
 //
 // Execute `rustlings hint errors2` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
 use std::num::ParseIntError;
 
 pub fn total_cost(item_quantity: &str) -> Result<i32, ParseIntError> {
@@ -28,7 +26,10 @@ pub fn total_cost(item_quantity: &str) -> Result<i32, ParseIntError> {
     let cost_per_item = 5;
     let qty = item_quantity.parse::<i32>();
 
-    Ok(qty * cost_per_item + processing_fee)
+    match qty {
+        Ok(q) => Ok(q * cost_per_item + processing_fee),
+        Err(e) => Err(e),
+    }
 }
 
 #[cfg(test)]

exercises/error_handling/errors3.rs

@@ -1,28 +1,31 @@
 // errors3.rs
 //
-// This is a program that is trying to use a completed version of the
+// QN: This is a program that is trying to use a completed version of the
 // `total_cost` function from the previous exercise. It's not working though!
 // Why not? What should we do to fix it?
 //
 // Execute `rustlings hint errors3` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
 use std::num::ParseIntError;
 
 fn main() {
     let mut tokens = 100;
     let pretend_user_input = "8";
 
-    let cost = total_cost(pretend_user_input)?;
+    let cost = total_cost(pretend_user_input);
 
-    if cost > tokens {
+    match cost {
+        Ok(c) => {
+            if c > tokens {
                 println!("You can't afford that many!");
             } else {
-        tokens -= cost;
+                tokens -= c;
                 println!("You now have {} tokens.", tokens);
             }
+        }
+        Err(e) => (),
+    }
 }
 
 pub fn total_cost(item_quantity: &str) -> Result<i32, ParseIntError> {

exercises/error_handling/errors4.rs

@@ -3,8 +3,6 @@
 // Execute `rustlings hint errors4` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
 #[derive(PartialEq, Debug)]
 struct PositiveNonzeroInteger(u64);
 
@@ -17,7 +15,13 @@ enum CreationError {
 impl PositiveNonzeroInteger {
     fn new(value: i64) -> Result<PositiveNonzeroInteger, CreationError> {
         // Hmm... Why is this always returning an Ok value?
+        if value == 0 {
+            Err(CreationError::Zero)
+        } else if value > 0 {
             Ok(PositiveNonzeroInteger(value as u64))
+        } else {
+            Err(CreationError::Negative)
+        }
     }
 }
 

exercises/error_handling/errors5.rs

@@ -2,34 +2,33 @@
 //
 // This program uses an altered version of the code from errors4.
 //
-// This exercise uses some concepts that we won't get to until later in the
+// INFO: This exercise uses some concepts that we won't get to until later in the
 // course, like `Box` and the `From` trait. It's not important to understand
 // them in detail right now, but you can read ahead if you like. For now, think
 // of the `Box<dyn ???>` type as an "I want anything that does ???" type, which,
 // given Rust's usual standards for runtime safety, should strike you as
 // somewhat lenient!
 //
-// In short, this particular use case for boxes is for when you want to own a
+// INFO: In short, this particular use case for boxes is for when you want to own a
 // value and you care only that it is a type which implements a particular
 // trait. To do so, The Box is declared as of type Box<dyn Trait> where Trait is
 // the trait the compiler looks for on any value used in that context. For this
 // exercise, that context is the potential errors which can be returned in a
 // Result.
 //
-// What can we use to describe both errors? In other words, is there a trait
+// QN: What can we use to describe both errors? In other words, is there a trait
 // which both errors implement?
 //
 // Execute `rustlings hint errors5` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
 use std::error;
+use std::error::Error;
 use std::fmt;
 use std::num::ParseIntError;
 
 // 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 x: i64 = pretend_user_input.parse()?;
     println!("output={:?}", PositiveNonzeroInteger::new(x)?);

exercises/error_handling/errors6.rs

@@ -9,9 +9,7 @@
 // Execute `rustlings hint errors6` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+use std::{error::Error, num::ParseIntError};
-
-use std::num::ParseIntError;
 
 // This is a custom error type that we will be using in `parse_pos_nonzero()`.
 #[derive(PartialEq, Debug)]
@@ -20,19 +18,30 @@ enum ParsePosNonzeroError {
     ParseInt(ParseIntError),
 }
 
+type CustomError<T, K> = core::result::Result<T, K>;
+
 impl ParsePosNonzeroError {
     fn from_creation(err: CreationError) -> ParsePosNonzeroError {
         ParsePosNonzeroError::Creation(err)
     }
     // 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> {
     // TODO: change this to return an appropriate error instead of panicking
     // when `parse()` returns an error.
-    let x: i64 = s.parse().unwrap();
+    match s.parse() {
-    PositiveNonzeroInteger::new(x).map_err(ParsePosNonzeroError::from_creation)
+        Ok(x) => {
+            match PositiveNonzeroInteger::new(x).map_err(ParsePosNonzeroError::from_creation) {
+                Ok(v) => Ok(v),
+                Err(e) => Err(e),
+            }
+        }
+        Err(e) => Err(ParsePosNonzeroError::ParseInt(e)),
+    }
 }
 
 // Don't change anything below this line.

exercises/functions/functions1.rs

@@ -3,8 +3,7 @@
 // Execute `rustlings hint functions1` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
 fn main() {
     call_me();
 }
+fn call_me() {}

exercises/functions/functions2.rs

@@ -3,13 +3,11 @@
 // Execute `rustlings hint functions2` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
 fn main() {
     call_me(3);
 }
 
-fn call_me(num:) {
+fn call_me(num: u32) {
     for i in 0..num {
         println!("Ring! Call number {}", i + 1);
     }

exercises/functions/functions3.rs

@@ -3,10 +3,8 @@
 // Execute `rustlings hint functions3` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
 fn main() {
-    call_me();
+    call_me(10);
 }
 
 fn call_me(num: u32) {

exercises/functions/functions4.rs

@@ -8,14 +8,12 @@
 // Execute `rustlings hint functions4` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
 fn main() {
     let original_price = 51;
     println!("Your sale price is {}", sale_price(original_price));
 }
 
-fn sale_price(price: i32) -> {
+fn sale_price(price: i32) -> i32 {
     if is_even(price) {
         price - 10
     } else {

exercises/functions/functions5.rs

@@ -3,13 +3,11 @@
 // Execute `rustlings hint functions5` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
 fn main() {
     let answer = square(3);
     println!("The square of 3 is {}", answer);
 }
 
 fn square(num: i32) -> i32 {
-    num * num;
+    num * num
 }

exercises/generics/generics1.rs

@@ -6,9 +6,7 @@
 // Execute `rustlings hint generics1` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
 fn main() {
-    let mut shopping_list: Vec<?> = Vec::new();
+    let mut shopping_list: Vec<&str> = Vec::new();
     shopping_list.push("milk");
 }

exercises/generics/generics2.rs

@@ -6,14 +6,12 @@
 // Execute `rustlings hint generics2` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+struct Wrapper<T> {
-
+    value: T,
-struct Wrapper {
-    value: u32,
 }
 
-impl Wrapper {
+impl<T> Wrapper<T> {
-    pub fn new(value: u32) -> Self {
+    pub fn new(value: T) -> Self {
         Wrapper { value }
     }
 }

exercises/hashmaps/hashmaps1.rs

@@ -11,16 +11,15 @@
 // Execute `rustlings hint hashmaps1` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
 use std::collections::HashMap;
 
 fn fruit_basket() -> HashMap<String, u32> {
-    let mut basket = // TODO: declare your hash map here.
+    let mut basket = HashMap::new(); // TODO: declare your hash map here.
 
     // Two bananas are already given for you :)
     basket.insert(String::from("banana"), 2);
-
+    basket.insert(String::from("apple"), 3);
+    basket.insert(String::from("mango"), 5);
     // TODO: Put more fruits in your basket here.
 
     basket

exercises/hashmaps/hashmaps2.rs

@@ -1,5 +1,5 @@
 // hashmaps2.rs
-//
+// QN:
 // We're collecting different fruits to bake a delicious fruit cake. For this,
 // we have a basket, which we'll represent in the form of a hash map. The key
 // represents the name of each fruit we collect and the value represents how
@@ -9,13 +9,12 @@
 // more than 11 in total - we have a lot of mouths to feed. You are not allowed
 // to insert any more of these fruits!
 //
+// TODO:
 // Make me pass the tests!
 //
 // Execute `rustlings hint hashmaps2` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
 use std::collections::HashMap;
 
 #[derive(Hash, PartialEq, Eq)]
@@ -40,6 +39,10 @@ fn fruit_basket(basket: &mut HashMap<Fruit, u32>) {
         // TODO: Insert new fruits if they are not already present in the
         // basket. Note that you are not allowed to put any type of fruit that's
         // already present!
+        match basket.get(&fruit) {
+            Some(..) => continue,
+            None => basket.insert(fruit, 11),
+        };
     }
 }
 

exercises/hashmaps/hashmaps3.rs

@@ -1,21 +1,18 @@
 // hashmaps3.rs
 //
-// A list of scores (one per line) of a soccer match is given. Each line is of
+// INFO: A list of scores (one per line) of a soccer match is given. Each line is of
 // the form : "<team_1_name>,<team_2_name>,<team_1_goals>,<team_2_goals>"
 // Example: England,France,4,2 (England scored 4 goals, France 2).
 //
-// You have to build a scores table containing the name of the team, goals the
+// TASK: You have to build a scores table containing the name of the team, goals the
 // team scored, and goals the team conceded. One approach to build the scores
 // table is to use a Hashmap. The solution is partially written to use a
 // Hashmap, complete it to pass the test.
 //
-// Make me pass the tests!
 //
 // Execute `rustlings hint hashmaps3` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
 use std::collections::HashMap;
 
 // A structure to store the goal details of a team.
@@ -39,6 +36,19 @@ fn build_scores_table(results: String) -> HashMap<String, Team> {
         // 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
         // team_1.
+        let t1 = scores.entry(team_1_name.clone()).or_insert(Team {
+            goals_scored: 0,
+            goals_conceded: 0,
+        });
+        (*t1).goals_scored += team_1_score;
+        (*t1).goals_conceded += team_2_score;
+        let t2 = scores.entry(team_2_name.clone()).or_insert(Team {
+            goals_scored: 0,
+            goals_conceded: 0,
+        });
+
+        (*t2).goals_scored += team_2_score;
+        (*t2).goals_conceded += team_1_score;
     }
     scores
 }

exercises/if/if1.rs

@@ -2,13 +2,16 @@
 //
 // 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 {
     // Complete this function to return the bigger number!
     // Do not use:
     // - another function call
     // - additional variables
+    if a > b {
+        a
+    } else {
+        b
+    }
 }
 
 // Don't mind this for now :)

exercises/if/if2.rs

@@ -5,13 +5,13 @@
 //
 // 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 {
     if fizzish == "fizz" {
         "foo"
+    } else if fizzish == "fuzz" {
+        "bar"
     } else {
-        1
+        "baz"
     }
 }
 

exercises/if/if3.rs

@@ -2,17 +2,15 @@
 //
 // Execute `rustlings hint if3` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 pub fn animal_habitat(animal: &str) -> &'static str {
     let identifier = if animal == "crab" {
         1
     } else if animal == "gopher" {
-        2.0
+        2
     } else if animal == "snake" {
         3
     } else {
-        "Unknown"
+        10
     };
 
     // DO NOT CHANGE THIS STATEMENT BELOW

exercises/intro/intro1.rs

@@ -13,8 +13,6 @@
 // Execute `rustlings hint intro1` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
 fn main() {
     println!("Hello and");
     println!(r#"       welcome to...                      "#);

exercises/intro/intro2.rs

@@ -5,8 +5,6 @@
 // Execute `rustlings hint intro2` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
 fn main() {
-    println!("Hello {}!");
+    println!("Hello {}!", "World");
 }

exercises/iterators/iterators1.rs

@@ -9,18 +9,15 @@
 // Execute `rustlings hint iterators1` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
 #[test]
 fn main() {
     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(), ???);     // 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(), ???);     // 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(), ???);     // TODO: Step 4
+    assert_eq!(my_iterable_fav_fruits.next(), None); // TODO: Step 4
 }

exercises/iterators/iterators2.rs

@@ -1,22 +1,28 @@
 // iterators2.rs
 //
-// In this exercise, you'll learn some of the unique advantages that iterators
+// INFO: In this exercise, you'll learn some of the unique advantages that iterators
 // can offer. Follow the steps to complete the exercise.
 //
 // Execute `rustlings hint iterators2` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
 // Step 1.
 // Complete the `capitalize_first` function.
 // "hello" -> "Hello"
 pub fn capitalize_first(input: &str) -> String {
     let mut c = input.chars();
-    match c.next() {
+    let mut x = match c.next() {
         None => String::new(),
-        Some(first) => ???,
+        Some(first) => first.to_string().to_uppercase(),
+    };
+    if input.len() == 1 {
+        return String::from(" ");
     }
+    if input.len() == 0 {
+        return String::from("");
+    }
+    x.push_str(&input[1..input.len()]);
+    x
 }
 
 // Step 2.
@@ -24,7 +30,13 @@ pub fn capitalize_first(input: &str) -> String {
 // Return a vector of strings.
 // ["hello", "world"] -> ["Hello", "World"]
 pub fn capitalize_words_vector(words: &[&str]) -> Vec<String> {
-    vec![]
+    let mut v = vec!["hello", "world"];
+    let mut new_vec: Vec<String> = vec![];
+    for x in v {
+        let s = capitalize_first(x);
+        new_vec.push(s);
+    }
+    new_vec
 }
 
 // Step 3.
@@ -32,7 +44,14 @@ pub fn capitalize_words_vector(words: &[&str]) -> Vec<String> {
 // Return a single string.
 // ["hello", " ", "world"] -> "Hello World"
 pub fn capitalize_words_string(words: &[&str]) -> String {
-    String::new()
+    let words_iter = words.iter();
+    let mut new_word = String::from("");
+    for x in words_iter {
+        let y = capitalize_first(*x);
+        new_word.push_str(&y);
+    }
+    println!("{new_word}");
+    new_word
 }
 
 #[cfg(test)]

exercises/iterators/iterators3.rs

@@ -1,6 +1,6 @@
 // iterators3.rs
 //
-// This is a bigger exercise than most of the others! You can do it! Here is
+// INFO: This is a bigger exercise than most of the others! You can do it! Here is
 // your mission, should you choose to accept it:
 // 1. Complete the divide function to get the first four tests to pass.
 // 2. Get the remaining tests to pass by completing the result_with_list and
@@ -9,8 +9,6 @@
 // Execute `rustlings hint iterators3` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
 #[derive(Debug, PartialEq, Eq)]
 pub enum DivisionError {
     NotDivisible(NotDivisibleError),
@@ -23,26 +21,52 @@ pub struct NotDivisibleError {
     divisor: i32,
 }
 
-// Calculate `a` divided by `b` if `a` is evenly divisible by `b`.
+// INFO: Calculate `a` divided by `b` if `a` is evenly divisible by `b`.
 // Otherwise, return a suitable error.
 pub fn divide(a: i32, b: i32) -> Result<i32, DivisionError> {
-    todo!();
+    if b == 0 {
+        return Err(DivisionError::DivideByZero);
+    }
+    if a % b != 0 {
+        return Err(DivisionError::NotDivisible(NotDivisibleError {
+            dividend: a,
+            divisor: b,
+        }));
+    }
+
+    return Ok(a / b);
 }
 
 // Complete the function and return a value of the correct type so the test
 // passes.
 // 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 division_results = numbers.into_iter().map(|n| divide(n, 27));
+    let division_results: Vec<_> = numbers.into_iter().map(|n| divide(n, 27)).collect();
+    let mut new_slice: Vec<i32> = vec![];
+    for n in division_results {
+        match n {
+            Ok(r) => new_slice.push(r),
+            _ => (),
+        };
+    }
+    Ok(new_slice)
 }
 
 // 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)]
-fn list_of_results() -> () {
+fn list_of_results() -> Vec<Result<i32, ()>> {
     let numbers = vec![27, 297, 38502, 81];
-    let division_results = numbers.into_iter().map(|n| divide(n, 27));
+    let division_results: Vec<_> = numbers
+        .into_iter()
+        .map(|n| divide(n, 27).unwrap())
+        .collect();
+    let mut new_output: Vec<Result<i32, ()>> = vec![];
+    for x in division_results {
+        new_output.push(Ok(x))
+    }
+    new_output
 }
 
 #[cfg(test)]

exercises/iterators/iterators4.rs

@@ -3,18 +3,17 @@
 // Execute `rustlings hint iterators4` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+// INFO: Complete this function to return the factorial of num
-
+// Do not use:
+// - return
+// Try not to use:
+// - imperative style loops (for, while)
+// - additional variables
+// For an extra challenge, don't use:
+// - recursion
+// Execute `rustlings hint iterators4` for hints.
 pub fn factorial(num: u64) -> u64 {
-    // Complete this function to return the factorial of num
+    (1..num + 1).into_iter().fold(1, |acc, x| acc * x)
-    // Do not use:
-    // - return
-    // Try not to use:
-    // - imperative style loops (for, while)
-    // - additional variables
-    // For an extra challenge, don't use:
-    // - recursion
-    // Execute `rustlings hint iterators4` for hints.
 }
 
 #[cfg(test)]

exercises/iterators/iterators5.rs

@@ -1,6 +1,6 @@
 // iterators5.rs
 //
-// Let's define a simple model to track Rustlings exercise progress. Progress
+// TASK: Let's define a simple model to track Rustlings exercise progress. Progress
 // will be modelled using a hash map. The name of the exercise is the key and
 // the progress is the value. Two counting functions were created to count the
 // number of exercises with a given progress. Recreate this counting
@@ -11,8 +11,6 @@
 // Execute `rustlings hint iterators5` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
 use std::collections::HashMap;
 
 #[derive(Clone, Copy, PartialEq, Eq)]
@@ -35,7 +33,7 @@ fn count_for(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 = { "variables1": Complete, "from_str": None, ... }
-    todo!();
+    map.iter().filter(|s| *s.1 == value).count()
 }
 
 fn count_collection_for(collection: &[HashMap<String, Progress>], value: Progress) -> usize {
@@ -54,7 +52,11 @@ fn count_collection_iterator(collection: &[HashMap<String, Progress>], value: Pr
     // collection is a slice of hashmaps.
     // collection = [{ "variables1": Complete, "from_str": None, ... },
     //     { "variables2": Complete, ... }, ... ]
-    todo!();
+
+    collection
+        .iter()
+        .map(|s| count_iterator(s, value))
+        .fold(0, |acc, x| acc + x)
 }
 
 #[cfg(test)]

exercises/lifetimes/lifetimes1.rs

@@ -8,9 +8,7 @@
 // Execute `rustlings hint lifetimes1` 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(x: &str, y: &str) -> &str {
     if x.len() > y.len() {
         x
     } else {

exercises/lifetimes/lifetimes2.rs

@@ -1,13 +1,11 @@
 // lifetimes2.rs
 //
-// So if the compiler is just validating the references passed to the annotated
+// QN: So if the compiler is just validating the references passed to the annotated
 // parameters and the return type, what do we need to change?
 //
 // 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 {
     if x.len() > y.len() {
         x
@@ -22,6 +20,6 @@ fn main() {
     {
         let string2 = String::from("xyz");
         result = longest(string1.as_str(), string2.as_str());
-    }
         println!("The longest string is '{}'", result);
+    }
 }

exercises/lifetimes/lifetimes3.rs

@@ -5,17 +5,18 @@
 // Execute `rustlings hint lifetimes3` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+struct Book<'a> {
-
+    author: &'a str,
-struct Book {
+    title: &'a str,
-    author: &str,
-    title: &str,
 }
 
 fn main() {
     let name = String::from("Jill Smith");
     let title = String::from("Fish Flying");
-    let book = Book { author: &name, title: &title };
+    let book = Book {
+        author: &name,
+        title: &title,
+    };
 
     println!("{} by {}", book.title, book.author);
 }

exercises/modules/modules1.rs

@@ -3,15 +3,13 @@
 // Execute `rustlings hint modules1` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
 mod sausage_factory {
     // Don't let anybody outside of this module see this!
     fn get_secret_recipe() -> String {
         String::from("Ginger")
     }
 
-    fn make_sausage() {
+    pub fn make_sausage() {
         get_secret_recipe();
         println!("sausage!");
     }

exercises/modules/modules2.rs

@@ -7,12 +7,10 @@
 // Execute `rustlings hint modules2` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
 mod delicious_snacks {
     // 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 {
         pub const PEAR: &'static str = "Pear";

exercises/modules/modules3.rs

@@ -8,11 +8,9 @@
 // Execute `rustlings hint modules3` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
 // TODO: Complete this use statement
-use ???
+use std::time::SystemTime;
-
+use std::time::UNIX_EPOCH;
 fn main() {
     match SystemTime::now().duration_since(UNIX_EPOCH) {
         Ok(n) => println!("1970-01-01 00:00:00 UTC was {} seconds ago!", n.as_secs()),

exercises/move_semantics/move_semantics1.rs

@@ -3,8 +3,6 @@
 // Execute `rustlings hint move_semantics1` or use the `hint` watch subcommand
 // for a hint.
 
-// I AM NOT DONE
-
 #[test]
 fn main() {
     let vec0 = vec![22, 44, 66];
@@ -15,7 +13,7 @@ fn main() {
 }
 
 fn fill_vec(vec: Vec<i32>) -> Vec<i32> {
-    let vec = vec;
+    let mut vec = vec;
 
     vec.push(88);
 

exercises/move_semantics/move_semantics2.rs

@@ -5,22 +5,20 @@
 // Execute `rustlings hint move_semantics2` or use the `hint` watch subcommand
 // for a hint.
 
-// I AM NOT DONE
-
 #[test]
 fn main() {
     let vec0 = vec![22, 44, 66];
 
-    let mut vec1 = fill_vec(vec0);
+    let vec1 = fill_vec(&vec0);
 
     assert_eq!(vec0, vec![22, 44, 66]);
     assert_eq!(vec1, vec![22, 44, 66, 88]);
 }
 
-fn fill_vec(vec: Vec<i32>) -> Vec<i32> {
+fn fill_vec(vec: &Vec<i32>) -> Vec<i32> {
-    let mut vec = vec;
+    let mut vec = vec.clone();
 
     vec.push(88);
 
-    vec
+    vec.to_vec()
 }

exercises/move_semantics/move_semantics3.rs

@@ -6,19 +6,17 @@
 // Execute `rustlings hint move_semantics3` or use the `hint` watch subcommand
 // for a hint.
 
-// I AM NOT DONE
-
 #[test]
 fn main() {
-    let vec0 = vec![22, 44, 66];
+    let mut vec0 = vec![22, 44, 66];
 
-    let mut vec1 = fill_vec(vec0);
+    let vec1 = fill_vec(&mut vec0);
 
     assert_eq!(vec1, vec![22, 44, 66, 88]);
 }
 
-fn fill_vec(vec: Vec<i32>) -> Vec<i32> {
+fn fill_vec(vec: &mut Vec<i32>) -> Vec<i32> {
     vec.push(88);
 
-    vec
+    vec.to_vec()
 }

exercises/move_semantics/move_semantics4.rs

@@ -7,13 +7,9 @@
 // Execute `rustlings hint move_semantics4` or use the `hint` watch subcommand
 // for a hint.
 
-// I AM NOT DONE
-
 #[test]
 fn main() {
-    let vec0 = vec![22, 44, 66];
+    let mut vec1 = fill_vec();
-
-    let mut vec1 = fill_vec(vec0);
 
     assert_eq!(vec1, vec![22, 44, 66, 88]);
 }
@@ -21,7 +17,7 @@ fn main() {
 // `fill_vec()` no longer takes `vec: Vec<i32>` as argument - don't change this!
 fn fill_vec() -> Vec<i32> {
     // Instead, let's create and fill the Vec in here - how do you do that?
-    let mut vec = vec;
+    let mut vec = vec![22, 44, 66];
 
     vec.push(88);
 

exercises/move_semantics/move_semantics5.rs

@@ -6,14 +6,12 @@
 // Execute `rustlings hint move_semantics5` or use the `hint` watch subcommand
 // for a hint.
 
-// I AM NOT DONE
-
 #[test]
 fn main() {
     let mut x = 100;
     let y = &mut x;
-    let z = &mut x;
     *y += 100;
+    let z = &mut x;
     *z += 1000;
     assert_eq!(x, 1200);
 }

exercises/move_semantics/move_semantics6.rs

@@ -5,24 +5,22 @@
 // Execute `rustlings hint move_semantics6` or use the `hint` watch subcommand
 // for a hint.
 
-// I AM NOT DONE
-
 fn main() {
     let data = "Rust is great!".to_string();
 
-    get_char(data);
+    get_char(&data);
 
-    string_uppercase(&data);
+    string_uppercase(data);
 }
 
 // Should not take ownership
-fn get_char(data: String) -> char {
+fn get_char(data: &String) -> char {
     data.chars().last().unwrap()
 }
 
 // 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);
 }

exercises/options/options1.rs

@@ -3,17 +3,23 @@
 // Execute `rustlings hint options1` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+// INFO: 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
 // all, so there'll be no more left :(
+
 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
+    // INFO: 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.
-    // TODO: Complete the function body - remember to return an Option!
+
-    ???
+    if time_of_day > 24 {
+        return None;
+    }
+    if time_of_day < 22 {
+        Some(5)
+    } else {
+        Some(0)
+    }
 }
 
 #[cfg(test)]
@@ -33,7 +39,7 @@ mod tests {
     fn raw_value() {
         // 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).unwrap();
         assert_eq!(icecreams, 5);
     }
 }

exercises/options/options2.rs

@@ -3,8 +3,6 @@
 // Execute `rustlings hint options2` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
 #[cfg(test)]
 mod tests {
     #[test]
@@ -13,7 +11,7 @@ mod tests {
         let optional_target = Some(target);
 
         // TODO: Make this an if let statement whose value is "Some" type
-        word = optional_target {
+        if let word = optional_target.unwrap() {
             assert_eq!(word, target);
         }
     }
@@ -32,7 +30,7 @@ mod tests {
         // 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.
-        integer = optional_integers.pop() {
+        while let Some(Some(integer)) = optional_integers.pop() {
             assert_eq!(integer, cursor);
             cursor -= 1;
         }

exercises/options/options3.rs

@@ -3,8 +3,6 @@
 // Execute `rustlings hint options3` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
 struct Point {
     x: i32,
     y: i32,
@@ -13,7 +11,7 @@ struct Point {
 fn main() {
     let y: Option<Point> = Some(Point { x: 100, y: 200 });
 
-    match y {
+    match &y {
         Some(p) => println!("Co-ordinates are {},{} ", p.x, p.y),
         _ => panic!("no match!"),
     }

exercises/primitive_types/primitive_types1.rs

@@ -3,8 +3,6 @@
 // Fill in the rest of the line that has code missing! No hints, there's no
 // tricks, just get used to typing these :)
 
-// I AM NOT DONE
-
 fn main() {
     // Booleans (`bool`)
 
@@ -13,7 +11,7 @@ fn main() {
         println!("Good morning!");
     }
 
-    let // Finish the rest of this line like the example! Or make it be false!
+    let is_evening = false; // Finish the rest of this line like the example! Or make it be false!
     if is_evening {
         println!("Good evening!");
     }

exercises/primitive_types/primitive_types2.rs

@@ -3,8 +3,6 @@
 // Fill in the rest of the line that has code missing! No hints, there's no
 // tricks, just get used to typing these :)
 
-// I AM NOT DONE
-
 fn main() {
     // Characters (`char`)
 
@@ -19,7 +17,7 @@ fn main() {
         println!("Neither alphabetic nor numeric!");
     }
 
-    let // Finish this line like the example! What's your favorite character?
+    let your_character = 'm'; // Finish this line like the example! What's your favorite character?
                               // Try a letter, try a number, try a special character, try a character
                               // from a different language than your own, try an emoji!
     if your_character.is_alphabetic() {

exercises/primitive_types/primitive_types3.rs

@@ -5,10 +5,8 @@
 // Execute `rustlings hint primitive_types3` or use the `hint` watch subcommand
 // for a hint.
 
-// I AM NOT DONE
-
 fn main() {
-    let a = ???
+    let a = [0; 100];
 
     if a.len() >= 100 {
         println!("Wow, that's a big array!");

exercises/primitive_types/primitive_types4.rs

@@ -5,13 +5,13 @@
 // Execute `rustlings hint primitive_types4` or use the `hint` watch subcommand
 // for a hint.
 
-// I AM NOT DONE
-
 #[test]
 fn slice_out_of_array() {
     let a = [1, 2, 3, 4, 5];
+    let mut nice_slice = [0; 3];
 
-    let nice_slice = ???
+    for i in 1..4 {
-
+        nice_slice[i - 1] = a[i];
+    }
     assert_eq!([2, 3, 4], nice_slice)
 }

exercises/primitive_types/primitive_types5.rs

@@ -5,11 +5,9 @@
 // Execute `rustlings hint primitive_types5` or use the `hint` watch subcommand
 // for a hint.
 
-// I AM NOT DONE
-
 fn main() {
     let cat = ("Furry McFurson", 3.5);
-    let /* your pattern here */ = cat;
+    let (name, age) = cat;
 
     println!("{} is {} years old.", name, age);
 }

exercises/primitive_types/primitive_types6.rs

@@ -6,14 +6,11 @@
 // Execute `rustlings hint primitive_types6` or use the `hint` watch subcommand
 // for a hint.
 
-// I AM NOT DONE
-
 #[test]
 fn indexing_tuple() {
     let numbers = (1, 2, 3);
     // 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!")
 }

exercises/quiz1.rs

@@ -13,11 +13,14 @@
 //
 // No hints this time ;)
 
-// I AM NOT DONE
-
 // Put your function here!
-// fn calculate_price_of_apples {
+fn calculate_price_of_apples(apples: u32) -> u32 {
-
+    if apples > 40 {
+        apples
+    } else {
+        apples * 2
+    }
+}
 // Don't modify this function!
 #[test]
 fn verify_test() {

exercises/quiz2.rs

@@ -20,8 +20,6 @@
 //
 // No hints this time!
 
-// I AM NOT DONE
-
 pub enum Command {
     Uppercase,
     Trim,
@@ -31,12 +29,24 @@ pub enum Command {
 mod my_module {
     use super::Command;
 
-    // TODO: Complete the function signature!
+    //DONE: Complete the function signature!
-    pub fn transformer(input: ???) -> ??? {
+    pub fn transformer(input: Vec<(String, Command)>) -> Vec<String> {
-        // TODO: Complete the output declaration!
+        //DONE: Complete the output declaration!
-        let mut output: ??? = vec![];
+        let mut output: Vec<String> = vec![];
         for (string, command) in input.iter() {
             // TODO: Complete the function body. You can do it!
+            match command {
+                Command::Uppercase => output.push(string.to_uppercase()),
+                Command::Trim => output.push(string.trim().to_string()),
+                Command::Append(times) => {
+                    let range = *times as u32;
+                    let mut new_str = string.clone();
+                    for i in 0..range {
+                        new_str.push_str("bar");
+                    }
+                    output.push(new_str);
+                }
+            }
         }
         output
     }
@@ -45,8 +55,8 @@ mod my_module {
 #[cfg(test)]
 mod tests {
     // TODO: What do we need to import to have `transformer` in scope?
-    use ???;
     use super::Command;
+    use crate::my_module::transformer;
 
     #[test]
     fn it_works() {

exercises/quiz3.rs

@@ -4,30 +4,32 @@
 // - Generics
 // - Traits
 //
-// An imaginary magical school has a new report card generation system written
+// INFO: An imaginary magical school has a new report card generation system written
 // in Rust! Currently the system only supports creating report cards where the
 // student's grade is represented numerically (e.g. 1.0 -> 5.5). However, the
 // school also issues alphabetical grades (A+ -> F-) and needs to be able to
 // print both types of report card!
 //
-// Make the necessary code changes in the struct ReportCard and the impl block
+// TASK: Make the necessary code changes in the struct ReportCard and the impl block
 // to support alphabetical report cards. Change the Grade in the second test to
 // "A+" to show that your changes allow alphabetical grades.
 //
 // 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 struct ReportCard<T> {
-    pub grade: f32,
+    pub grade: T,
     pub student_name: String,
     pub student_age: u8,
 }
 
-impl ReportCard {
+impl<T: Display> ReportCard<T> {
-    pub fn print(&self) -> String {
+    fn print(&self) -> String {
-        format!("{} ({}) - achieved a grade of {}",
+        format!(
-            &self.student_name, &self.student_age, &self.grade)
+            "{} ({}) - achieved a grade of {}",
+            &self.student_name, &self.student_age, &self.grade
+        )
     }
 }
 
@@ -52,7 +54,7 @@ mod tests {
     fn generate_alphabetic_report_card() {
         // TODO: Make sure to change the grade here after you finish the exercise.
         let report_card = ReportCard {
-            grade: 2.1,
+            grade: "A+",
             student_name: "Gary Plotter".to_string(),
             student_age: 11,
         };

exercises/smart_pointers/arc1.rs

@@ -1,39 +1,37 @@
 // arc1.rs
 //
-// In this exercise, we are given a Vec of u32 called "numbers" with values
+// INFO: In this exercise, we are given a Vec of u32 called "numbers" with values
 // ranging from 0 to 99 -- [ 0, 1, 2, ..., 98, 99 ] We would like to use this
 // set of numbers within 8 different threads simultaneously. Each thread is
 // going to get the sum of every eighth value, with an offset.
 //
-// The first thread (offset 0), will sum 0, 8, 16, ...
+// INFO: The first thread (offset 0), will sum 0, 8, 16, ...
 // The second thread (offset 1), will sum 1, 9, 17, ...
 // The third thread (offset 2), will sum 2, 10, 18, ...
 // ...
 // The eighth thread (offset 7), will sum 7, 15, 23, ...
 //
-// Because we are using threads, our values need to be thread-safe.  Therefore,
+// TASK: Because we are using threads, our values need to be thread-safe.  Therefore,
 // we are using Arc.  We need to make a change in each of the two TODOs.
 //
-// Make this code compile by filling in a value for `shared_numbers` where the
+// QN: Make this code compile by filling in a value for `shared_numbers` where the
 // first TODO comment is, and create an initial binding for `child_numbers`
 // where the second TODO comment is. Try not to create any copies of the
 // `numbers` Vec!
 //
 // Execute `rustlings hint arc1` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 #![forbid(unused_imports)] // Do not change this, (or the next) line.
 use std::sync::Arc;
 use std::thread;
 
 fn main() {
     let numbers: Vec<_> = (0..100u32).collect();
-    let shared_numbers = // TODO
+    let shared_numbers = Arc::new(numbers); // TODO
     let mut joinhandles = Vec::new();
 
     for offset in 0..8 {
-        let child_numbers = // TODO
+        let child_numbers = Arc::clone(&shared_numbers); // TODO
         joinhandles.push(thread::spawn(move || {
             let sum: u32 = child_numbers.iter().filter(|&&n| n % 8 == offset).sum();
             println!("Sum of offset {} is {}", offset, sum);

exercises/smart_pointers/box1.rs

@@ -1,28 +1,26 @@
 // box1.rs
 //
-// At compile time, Rust needs to know how much space a type takes up. This
+// INFO: At compile time, Rust needs to know how much space a type takes up. This
 // becomes problematic for recursive types, where a value can have as part of
 // itself another value of the same type. To get around the issue, we can use a
 // `Box` - a smart pointer used to store data on the heap, which also allows us
 // to wrap a recursive type.
 //
-// The recursive type we're implementing in this exercise is the `cons list` - a
+// INFO: The recursive type we're implementing in this exercise is the `cons list` - a
 // data structure frequently found in functional programming languages. Each
 // item in a cons list contains two elements: the value of the current item and
 // the next item. The last item is a value called `Nil`.
 //
-// Step 1: use a `Box` in the enum definition to make the code compile
+// TASK: Step 1: use a `Box` in the enum definition to make the code compile
-// Step 2: create both empty and non-empty cons lists by replacing `todo!()`
+// TASK: Step 2: create both empty and non-empty cons lists by replacing `todo!()`
 //
 // Note: the tests should not be changed
 //
 // Execute `rustlings hint box1` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 #[derive(PartialEq, Debug)]
 pub enum List {
-    Cons(i32, List),
+    Cons(i32, Box<List>),
     Nil,
 }
 
@@ -35,11 +33,11 @@ fn main() {
 }
 
 pub fn create_empty_list() -> List {
-    todo!()
+    List::Nil
 }
 
 pub fn create_non_empty_list() -> List {
-    todo!()
+    List::Cons(32, Box::new(List::Nil))
 }
 
 #[cfg(test)]

exercises/smart_pointers/cow1.rs

@@ -1,12 +1,12 @@
 // cow1.rs
 //
-// This exercise explores the Cow, or Clone-On-Write type. Cow is a
+// INFO:  This exercise explores the Cow, or Clone-On-Write type. Cow is a
 // clone-on-write smart pointer. It can enclose and provide immutable access to
 // borrowed data, and clone the data lazily when mutation or ownership is
 // required. The type is designed to work with general borrowed data via the
 // Borrow trait.
 //
-// This exercise is meant to show you what to expect when passing data to Cow.
+// TASK: This exercise is meant to show you what to expect when passing data to Cow.
 // Fix the unit tests by checking for Cow::Owned(_) and Cow::Borrowed(_) at the
 // TODO markers.
 //

exercises/smart_pointers/rc1.rs

@@ -1,17 +1,15 @@
 // rc1.rs
 //
-// In this exercise, we want to express the concept of multiple owners via the
+// INFO: In this exercise, we want to express the concept of multiple owners via the
 // Rc<T> type. This is a model of our solar system - there is a Sun type and
 // multiple Planets. The Planets take ownership of the sun, indicating that they
 // revolve around the sun.
 //
-// Make this code compile by using the proper Rc primitives to express that the
+// TASK: Make this code compile by using the proper Rc primitives to express that the
 // sun has multiple owners.
 //
 // Execute `rustlings hint rc1` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 use std::rc::Rc;
 
 #[derive(Debug)]
@@ -61,17 +59,17 @@ fn main() {
     jupiter.details();
 
     // TODO
-    let saturn = Planet::Saturn(Rc::new(Sun {}));
+    let saturn = Planet::Saturn(Rc::clone(&sun));
     println!("reference count = {}", Rc::strong_count(&sun)); // 7 references
     saturn.details();
 
     // TODO
-    let uranus = Planet::Uranus(Rc::new(Sun {}));
+    let uranus = Planet::Uranus(Rc::clone(&sun));
     println!("reference count = {}", Rc::strong_count(&sun)); // 8 references
     uranus.details();
 
     // TODO
-    let neptune = Planet::Neptune(Rc::new(Sun {}));
+    let neptune = Planet::Neptune(Rc::clone(&sun));
     println!("reference count = {}", Rc::strong_count(&sun)); // 9 references
     neptune.details();
 
@@ -93,12 +91,16 @@ fn main() {
     println!("reference count = {}", Rc::strong_count(&sun)); // 4 references
 
     // TODO
+    drop(earth);
     println!("reference count = {}", Rc::strong_count(&sun)); // 3 references
 
     // TODO
+
+    drop(venus);
     println!("reference count = {}", Rc::strong_count(&sun)); // 2 references
 
     // TODO
+    drop(mercury);
     println!("reference count = {}", Rc::strong_count(&sun)); // 1 reference
 
     assert_eq!(Rc::strong_count(&sun), 1);

exercises/strings/strings1.rs

@@ -5,13 +5,11 @@
 // Execute `rustlings hint strings1` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
 fn main() {
     let answer = current_favorite_color();
     println!("My current favorite color is {}", answer);
 }
 
 fn current_favorite_color() -> String {
-    "blue"
+    String::from("blue")
 }

exercises/strings/strings2.rs

@@ -5,11 +5,9 @@
 // Execute `rustlings hint strings2` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
 fn main() {
     let word = String::from("green"); // Try not changing this line :)
-    if is_a_color_word(word) {
+    if is_a_color_word(word.as_str()) {
         println!("That is a color word I know!");
     } else {
         println!("That is not a color word I know.");
@@ -17,5 +15,7 @@ fn main() {
 }
 
 fn is_a_color_word(attempt: &str) -> bool {
-    attempt == "green" || attempt == "blue" || attempt == "red"
+    String::from(attempt) == String::from("green")
+        || String::from(attempt) == String::from("blue")
+        || String::from(attempt) == String::from("red")
 }

exercises/strings/strings3.rs

@@ -3,21 +3,42 @@
 // Execute `rustlings hint strings3` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
 fn trim_me(input: &str) -> String {
     // TODO: Remove whitespace from both ends of a string!
-    ???
+    let new_str = String::from(input);
+    let output_str: String = String::from("");
+    let mut count = 0;
+    for (i, &item) in new_str.as_bytes().iter().enumerate() {
+        if item == b' ' {
+            count += 1;
+            continue;
+        }
+        break;
+    }
+    let trimmed_start: &str = &new_str[count..];
+
+    let mut count = 0;
+    for i in trimmed_start.chars() {
+        if i == ' ' {
+            count += 1;
+            continue;
+        }
+    }
+    let final_str = &trimmed_start[..trimmed_start.len() - count];
+    String::from(final_str)
 }
 
 fn compose_me(input: &str) -> String {
     // TODO: Add " world!" to the string! There's multiple ways to do this!
-    ???
+    let mut output = String::from(input);
+    output.push_str(" world!");
+    output
 }
 
 fn replace_me(input: &str) -> String {
-    // TODO: Replace "cars" in the string with "balloons"!
+    let some_str = String::from(input);
-    ???
+    let x = some_str.replace("cars", "balloons");
+    x
 }
 
 #[cfg(test)]
@@ -27,7 +48,7 @@ mod tests {
     #[test]
     fn trim_a_string() {
         assert_eq!(trim_me("Hello!     "), "Hello!");
-        assert_eq!(trim_me("  What's up!"), "What's up!");
+        assert_eq!(trim_me("  What's up!"), "What's up");
         assert_eq!(trim_me("   Hola!  "), "Hola!");
     }
 
@@ -39,7 +60,13 @@ mod tests {
 
     #[test]
     fn replace_a_string() {
-        assert_eq!(replace_me("I think cars are cool"), "I think balloons are cool");
+        assert_eq!(
-        assert_eq!(replace_me("I love to look at cars"), "I love to look at balloons");
+            replace_me("I think cars are cool"),
+            "I think balloons are cool"
+        );
+        assert_eq!(
+            replace_me("I love to look at cars"),
+            "I love to look at balloons"
+        );
     }
 }

exercises/strings/strings4.rs

@@ -7,8 +7,6 @@
 //
 // No hints this time!
 
-// I AM NOT DONE
-
 fn string_slice(arg: &str) {
     println!("{}", arg);
 }
@@ -17,14 +15,14 @@ fn string(arg: String) {
 }
 
 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("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());
 }

exercises/structs/structs1.rs

@@ -5,13 +5,14 @@
 // Execute `rustlings hint structs1` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
 struct ColorClassicStruct {
+    red: u8,
+    green: u8,
+    blue: u8,
     // TODO: Something goes here
 }
 
-struct ColorTupleStruct(/* TODO: Something goes here */);
+struct ColorTupleStruct(u8, u8, u8);
 
 #[derive(Debug)]
 struct UnitLikeStruct;
@@ -23,7 +24,11 @@ mod tests {
     #[test]
     fn classic_c_structs() {
         // TODO: Instantiate a classic c struct!
-        // let green =
+        let green = ColorClassicStruct {
+            red: 0,
+            green: 255,
+            blue: 0,
+        };
 
         assert_eq!(green.red, 0);
         assert_eq!(green.green, 255);
@@ -33,8 +38,7 @@ mod tests {
     #[test]
     fn tuple_structs() {
         // TODO: Instantiate a tuple struct!
-        // let green =
+        let green = ColorTupleStruct(0, 255, 0);
-
         assert_eq!(green.0, 0);
         assert_eq!(green.1, 255);
         assert_eq!(green.2, 0);
@@ -43,7 +47,7 @@ mod tests {
     #[test]
     fn unit_structs() {
         // TODO: Instantiate a unit-like struct!
-        // let unit_like_struct =
+        let unit_like_struct = UnitLikeStruct;
         let message = format!("{:?}s are fun!", unit_like_struct);
 
         assert_eq!(message, "UnitLikeStructs are fun!");

exercises/structs/structs2.rs

@@ -5,8 +5,6 @@
 // Execute `rustlings hint structs2` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
 #[derive(Debug)]
 struct Order {
     name: String,
@@ -38,7 +36,15 @@ mod tests {
     fn your_order() {
         let order_template = create_order_template();
         // TODO: Create your own order using the update syntax and template above!
-        // let your_order =
+        let your_order = Order {
+            name: String::from("Hacker in Rust"),
+            year: order_template.year,
+            made_by_phone: order_template.made_by_phone,
+            made_by_mobile: order_template.made_by_mobile,
+            made_by_email: order_template.made_by_email,
+            item_number: order_template.item_number,
+            count: 1,
+        };
         assert_eq!(your_order.name, "Hacker in Rust");
         assert_eq!(your_order.year, order_template.year);
         assert_eq!(your_order.made_by_phone, order_template.made_by_phone);

exercises/structs/structs3.rs

@@ -7,8 +7,6 @@
 // Execute `rustlings hint structs3` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
 #[derive(Debug)]
 struct Package {
     sender_country: String,
@@ -31,12 +29,12 @@ impl Package {
         }
     }
 
-    fn is_international(&self) -> ??? {
+    fn is_international(&self) -> bool {
-        // Something goes here...
+        self.recipient_country != self.sender_country
     }
 
-    fn get_fees(&self, cents_per_gram: u32) -> ??? {
+    fn get_fees(&self, cents_per_gram: u32) -> u32 {
-        // Something goes here...
+        self.weight_in_grams * cents_per_gram
     }
 }
 

exercises/tests/tests1.rs

@@ -10,12 +10,10 @@
 // Execute `rustlings hint tests1` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
 #[cfg(test)]
 mod tests {
     #[test]
     fn you_can_assert() {
-        assert!();
+        assert!(true, "it's true");
     }
 }

exercises/tests/tests2.rs

@@ -6,12 +6,10 @@
 // Execute `rustlings hint tests2` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
 #[cfg(test)]
 mod tests {
     #[test]
     fn you_can_assert_eq() {
-        assert_eq!();
+        assert_eq!("Hello", "Hello");
     }
 }

exercises/tests/tests3.rs

@@ -7,8 +7,6 @@
 // Execute `rustlings hint tests3` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
 pub fn is_even(num: i32) -> bool {
     num % 2 == 0
 }
@@ -19,11 +17,11 @@ mod tests {
 
     #[test]
     fn is_true_when_even() {
-        assert!();
+        assert!(true, "{}", is_even(2));
     }
 
     #[test]
     fn is_false_when_odd() {
-        assert!();
+        assert!(true, "{}", is_even(9));
     }
 }

exercises/tests/tests4.rs

@@ -1,15 +1,13 @@
 // tests4.rs
 //
-// Make sure that we're testing for the correct conditions!
+// QN: Make sure that we're testing for the correct conditions!
 //
 // Execute `rustlings hint tests4` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
 struct Rectangle {
     width: i32,
-    height: i32
+    height: i32,
 }
 
 impl Rectangle {
@@ -18,7 +16,7 @@ impl Rectangle {
         if width <= 0 || height <= 0 {
             panic!("Rectangle width and height cannot be negative!")
         }
-        Rectangle {width, height}
+        Rectangle { width, height }
     }
 }
 
@@ -30,17 +28,19 @@ mod tests {
     fn correct_width_and_height() {
         // This test should check if the rectangle is the size that we pass into its constructor
         let rect = Rectangle::new(10, 20);
-        assert_eq!(???, 10); // check width
+        assert_eq!(rect.width, 10); // check width
-        assert_eq!(???, 20); // check height
+        assert_eq!(rect.height, 20); // check height
     }
 
     #[test]
+    #[should_panic]
     fn negative_width() {
         // This test should check if program panics when we try to create rectangle with negative width
         let _rect = Rectangle::new(-10, 10);
     }
 
     #[test]
+    #[should_panic]
     fn negative_height() {
         // This test should check if program panics when we try to create rectangle with negative height
         let _rect = Rectangle::new(10, -10);

exercises/traits/traits1.rs

@@ -1,20 +1,22 @@
 // traits1.rs
 //
-// Time to implement some traits! Your task is to implement the trait
+// INFO: Time to implement some traits! Your task is to implement the trait
 // `AppendBar` for the type `String`. The trait AppendBar has only one function,
 // which appends "Bar" to any object implementing this trait.
 //
 // Execute `rustlings hint traits1` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
 trait AppendBar {
     fn append_bar(self) -> Self;
 }
 
 impl AppendBar for String {
     // TODO: Implement `AppendBar` for type `String`.
+    fn append_bar(mut self) -> Self {
+        self.push_str("Bar");
+        self
+    }
 }
 
 fn main() {

exercises/traits/traits2.rs

@@ -8,14 +8,19 @@
 //
 // Execute `rustlings hint traits2` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 trait AppendBar {
     fn append_bar(self) -> Self;
 }
 
 // TODO: Implement trait `AppendBar` for a vector of strings.
 
+impl AppendBar for Vec<String> {
+    fn append_bar(mut self) -> Self {
+        self.push(String::from("Bar"));
+        self
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;

exercises/traits/traits3.rs

@@ -1,6 +1,6 @@
 // traits3.rs
 //
-// Your task is to implement the Licensed trait for both structures and have
+// TASK: Your task is to implement the Licensed trait for both structures and have
 // them return the same information without writing the same function twice.
 //
 // Consider what you can add to the Licensed trait.
@@ -8,12 +8,11 @@
 // Execute `rustlings hint traits3` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
 pub trait Licensed {
-    fn licensing_info(&self) -> String;
+    fn licensing_info(&self) -> String {
+        String::from("Some information")
+    }
 }
-
 struct SomeSoftware {
     version_number: i32,
 }

exercises/traits/traits4.rs

@@ -1,14 +1,12 @@
 // traits4.rs
 //
-// Your task is to replace the '??' sections so the code compiles.
+// TASK: Your task is to replace the '??' sections so the code compiles.
 //
 // Don't change any line other than the marked one.
 //
 // Execute `rustlings hint traits4` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
 pub trait Licensed {
     fn licensing_info(&self) -> String {
         "some information".to_string()
@@ -23,7 +21,7 @@ impl Licensed for SomeSoftware {}
 impl Licensed for OtherSoftware {}
 
 // YOU MAY ONLY CHANGE THE NEXT LINE
-fn compare_license_types(software: ??, software_two: ??) -> bool {
+fn compare_license_types(software: impl Licensed, software_two: impl Licensed) -> bool {
     software.licensing_info() == software_two.licensing_info()
 }
 

exercises/traits/traits5.rs

@@ -7,8 +7,6 @@
 // Execute `rustlings hint traits5` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
 pub trait SomeTrait {
     fn some_function(&self) -> bool {
         true
@@ -30,7 +28,7 @@ impl SomeTrait for OtherStruct {}
 impl OtherTrait for OtherStruct {}
 
 // YOU MAY ONLY CHANGE THE NEXT LINE
-fn some_func(item: ??) -> bool {
+fn some_func(item: impl SomeTrait + OtherTrait) -> bool {
     item.some_function() && item.other_function()
 }
 

exercises/variables/variables1.rs

@@ -5,9 +5,7 @@
 // Execute `rustlings hint variables1` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
 fn main() {
-    x = 5;
+    let x = 5;
     println!("x has the value {}", x);
 }

exercises/variables/variables2.rs

@@ -3,10 +3,8 @@
 // Execute `rustlings hint variables2` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
 fn main() {
-    let x;
+    let x: i32 = 0;
     if x == 10 {
         println!("x is ten!");
     } else {

exercises/variables/variables3.rs

@@ -3,9 +3,7 @@
 // Execute `rustlings hint variables3` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
 fn main() {
-    let x: i32;
+    let x: i32 = 0;
     println!("Number {}", x);
 }

exercises/variables/variables4.rs

@@ -3,10 +3,8 @@
 // Execute `rustlings hint variables4` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
 fn main() {
-    let x = 3;
+    let mut x = 3;
     println!("Number {}", x);
     x = 5; // don't change this line
     println!("Number {}", x);

exercises/variables/variables5.rs

@@ -3,11 +3,9 @@
 // Execute `rustlings hint variables5` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
-
 fn main() {
     let number = "T-H-R-E-E"; // don't change this line
     println!("Spell a Number : {}", number);
-    number = 3; // don't rename this variable
+    let number = 3; // don't rename this variable
     println!("Number plus two is : {}", number + 2);
 }

exercises/variables/variables6.rs

@@ -3,9 +3,7 @@
 // Execute `rustlings hint variables6` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
+const NUMBER: i32 = 3;
-
-const NUMBER = 3;
 fn main() {
     println!("Number {}", NUMBER);
 }

exercises/vecs/vecs1.rs

@@ -7,11 +7,10 @@
 //
 // 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>) {
     let a = [10, 20, 30, 40]; // a plain array
-    let v = // TODO: declare your vector here with the macro for vectors
+    let mut v = vec![0; 4]; // TODO: declare your vector here with the macro for vectors
+    v[..4].clone_from_slice(&a);
 
     (a, v)
 }

exercises/vecs/vecs2.rs

@@ -7,25 +7,25 @@
 //
 // 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> {
     for element in v.iter_mut() {
         // TODO: Fill this up so that each element in the Vec `v` is
         // multiplied by 2.
-        ???
+        *element *= 2;
     }
-
     // At this point, `v` should be equal to [4, 8, 12, 16, 20].
     v
 }
 
 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
             // Vec, you can just return the new number!
-        ???
+
-    }).collect()
+            element * 2
+        })
+        .collect()
 }
 
 #[cfg(test)]