Initial commit

exercises/00_intro/README.md

@@ -0,0 +1,8 @@
+# Intro
+
+Rust uses the `print!` and `println!` macros to print text to the console.
+
+## Further information
+
+- [Hello World](https://doc.rust-lang.org/rust-by-example/hello.html)
+- [Formatted print](https://doc.rust-lang.org/rust-by-example/hello/print.html)

exercises/00_intro/intro1.rs

@@ -0,0 +1,24 @@
+// TODO: We sometimes encourage you to keep trying things on a given exercise
+// even after you already figured it out. If you got everything working and feel
+// ready for the next exercise, enter `n` in the terminal.
+//
+// The exercise file will be reloaded when you change one of the lines below!
+// Try adding a new `println!` and check the updated output in the terminal.
+
+fn main() {
+    println!(r#"       Welcome to...                      "#);
+    println!(r#"                 _   _ _                  "#);
+    println!(r#"  _ __ _   _ ___| |_| (_)_ __   __ _ ___  "#);
+    println!(r#" | '__| | | / __| __| | | '_ \ / _` / __| "#);
+    println!(r#" | |  | |_| \__ \ |_| | | | | | (_| \__ \ "#);
+    println!(r#" |_|   \__,_|___/\__|_|_|_| |_|\__, |___/ "#);
+    println!(r#"                               |___/      "#);
+    println!();
+    println!("This exercise compiles successfully. The remaining exercises contain a compiler");
+    println!("or logic error. The central concept behind Rustlings is to fix these errors and");
+    println!("solve the exercises. Good luck!");
+    println!();
+    println!("The file of this exercise is `exercises/00_intro/intro1.rs`. Have a look!");
+    println!("The current exercise path will be always shown under the progress bar.");
+    println!("You can click on the path to open the exercise file in your editor.");
+}

exercises/00_intro/intro2.rs

@@ -0,0 +1,4 @@
+fn main() {
+    // TODO: Fix the code to print "Hello world!".
+    println!("Hello world!");
+}

exercises/01_variables/README.md

@@ -0,0 +1,9 @@
+# Variables
+
+In Rust, variables are immutable by default.
+When a variable is immutable, once a value is bound to a name, you can’t change that value.
+You can make them mutable by adding `mut` in front of the variable name.
+
+## Further information
+
+- [Variables and Mutability](https://doc.rust-lang.org/book/ch03-01-variables-and-mutability.html)

exercises/01_variables/variables1.rs

@@ -0,0 +1,6 @@
+fn main() {
+    // TODO: Add the missing keyword.
+    let x = 5;
+
+    println!("x has the value {x}");
+}

exercises/01_variables/variables2.rs

@@ -0,0 +1,10 @@
+fn main() {
+    // TODO: Change the line below to fix the compiler error.
+    let x = 0;
+
+    if x == 10 {
+        println!("x is ten!");
+    } else {
+        println!("x is not ten!");
+    }
+}

exercises/01_variables/variables3.rs

@@ -0,0 +1,6 @@
+fn main() {
+    // TODO: Change the line below to fix the compiler error.
+    let x: i32 = 0;
+
+    println!("Number {x}");
+}

exercises/01_variables/variables4.rs

@@ -0,0 +1,8 @@
+// TODO: Fix the compiler error.
+fn main() {
+    let mut x = 3;
+    println!("Number {x}");
+
+    x = 5; // Don't change this line
+    println!("Number {x}");
+}

exercises/01_variables/variables5.rs

@@ -0,0 +1,8 @@
+fn main() {
+    let number = "T-H-R-E-E"; // Don't change this line
+    println!("Spell a number: {}", number);
+
+    // TODO: Fix the compiler error by changing the line below without renaming the variable.
+    let number = 3;
+    println!("Number plus two is: {}", number + 2);
+}

exercises/01_variables/variables6.rs

@@ -0,0 +1,6 @@
+// TODO: Change the line below to fix the compiler error.
+const NUMBER: i32 = 3;
+
+fn main() {
+    println!("Number: {NUMBER}");
+}

exercises/02_functions/README.md

@@ -0,0 +1,8 @@
+# Functions
+
+Here, you'll learn how to write functions and how the Rust compiler can help you debug errors even
+in more complex code.
+
+## Further information
+
+- [How Functions Work](https://doc.rust-lang.org/book/ch03-03-how-functions-work.html)

exercises/02_functions/functions1.rs

@@ -0,0 +1,7 @@
+// TODO: Add some function with the name `call_me` without arguments or a return value.
+
+fn call_me() {}
+
+fn main() {
+    call_me(); // Don't change this line
+}

exercises/02_functions/functions2.rs

@@ -0,0 +1,10 @@
+// TODO: Add the missing type of the argument `num` after the colon `:`.
+fn call_me(num: i32) {
+    for i in 0..num {
+        println!("Ring! Call number {}", i + 1);
+    }
+}
+
+fn main() {
+    call_me(3);
+}

exercises/02_functions/functions3.rs

@@ -0,0 +1,10 @@
+fn call_me(num: u8) {
+    for i in 0..num {
+        println!("Ring! Call number {}", i + 1);
+    }
+}
+
+fn main() {
+    // TODO: Fix the function call.
+    call_me(3);
+}

exercises/02_functions/functions4.rs

@@ -0,0 +1,22 @@
+// This store is having a sale where if the price is an even number, you get 10
+// Rustbucks off, but if it's an odd number, it's 3 Rustbucks off.
+// Don't worry about the function bodies themselves, we are only interested in
+// the signatures for now.
+
+fn is_even(num: i64) -> bool {
+    num % 2 == 0
+}
+
+// TODO: Fix the function signature.
+fn sale_price(price: i64) -> i64 {
+    if is_even(price) {
+        price - 10
+    } else {
+        price - 3
+    }
+}
+
+fn main() {
+    let original_price = 51;
+    println!("Your sale price is {}", sale_price(original_price));
+}

exercises/02_functions/functions5.rs

@@ -0,0 +1,9 @@
+// TODO: Fix the function body without changing the signature.
+fn square(num: i32) -> i32 {
+    num * num
+}
+
+fn main() {
+    let answer = square(3);
+    println!("The square of 3 is {answer}");
+}

exercises/03_if/README.md

@@ -0,0 +1,7 @@
+# If
+
+`if`, the most basic (but still surprisingly versatile!) type of control flow, is what you'll learn here.
+
+## Further information
+
+- [Control Flow - if expressions](https://doc.rust-lang.org/book/ch03-05-control-flow.html#if-expressions)

exercises/03_if/if1.rs

@@ -0,0 +1,37 @@
+fn bigger(a: i32, b: i32) -> i32 {
+    // TODO: Complete this function to return the bigger number!
+    // If both numbers are equal, any of them can be returned.
+    // Do not use:
+    // - another function call
+    // - additional variables
+    if a > b {
+        a
+    } else {
+        b
+    }
+}
+
+fn main() {
+    // You can optionally experiment here.
+}
+
+// Don't mind this for now :)
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn ten_is_bigger_than_eight() {
+        assert_eq!(10, bigger(10, 8));
+    }
+
+    #[test]
+    fn fortytwo_is_bigger_than_thirtytwo() {
+        assert_eq!(42, bigger(32, 42));
+    }
+
+    #[test]
+    fn equal_numbers() {
+        assert_eq!(42, bigger(42, 42));
+    }
+}

exercises/03_if/if2.rs

@@ -0,0 +1,39 @@
+// TODO: Fix the compiler error on this function.
+fn picky_eater(food: &str) -> &str {
+    if food == "strawberry" {
+        "Yummy!"
+    } else if food == "potato" {
+        "I guess I can eat that."
+    } else {
+        "No thanks!"
+    }
+}
+
+fn main() {
+    // You can optionally experiment here.
+}
+
+// TODO: Read the tests to understand the desired behavior.
+// Make all tests pass without changing them.
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn yummy_food() {
+        // This means that calling `picky_eater` with the argument "food" should return "Yummy!".
+        assert_eq!(picky_eater("strawberry"), "Yummy!");
+    }
+
+    #[test]
+    fn neutral_food() {
+        assert_eq!(picky_eater("potato"), "I guess I can eat that.");
+    }
+
+    #[test]
+    fn default_disliked_food() {
+        assert_eq!(picky_eater("broccoli"), "No thanks!");
+        assert_eq!(picky_eater("gummy bears"), "No thanks!");
+        assert_eq!(picky_eater("literally anything"), "No thanks!");
+    }
+}

exercises/03_if/if3.rs

@@ -0,0 +1,53 @@
+fn animal_habitat(animal: &str) -> &str {
+    // TODO: Fix the compiler error in the statement below.
+    let identifier = if animal == "crab" {
+        1
+    } else if animal == "gopher" {
+        2
+    } else if animal == "snake" {
+        3
+    } else {
+        4
+    };
+
+    // Don't change the expression below!
+    if identifier == 1 {
+        "Beach"
+    } else if identifier == 2 {
+        "Burrow"
+    } else if identifier == 3 {
+        "Desert"
+    } else {
+        "Unknown"
+    }
+}
+
+fn main() {
+    // You can optionally experiment here.
+}
+
+// Don't change the tests!
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn gopher_lives_in_burrow() {
+        assert_eq!(animal_habitat("gopher"), "Burrow")
+    }
+
+    #[test]
+    fn snake_lives_in_desert() {
+        assert_eq!(animal_habitat("snake"), "Desert")
+    }
+
+    #[test]
+    fn crab_lives_on_beach() {
+        assert_eq!(animal_habitat("crab"), "Beach")
+    }
+
+    #[test]
+    fn unknown_animal() {
+        assert_eq!(animal_habitat("dinosaur"), "Unknown")
+    }
+}