control flow, primitive types and vectors

exercises/03_if/if1.rs

@@ -4,10 +4,13 @@ fn bigger(a: i32, b: i32) -> i32 {
     // Do not use:
     // - another function call
     // - additional variables
+
+    if a > b { a } else { b }
 }
 
 fn main() {
     // You can optionally experiment here.
+    println!("{}", bigger(32, 42));
 }
 
 // Don't mind this for now :)

exercises/03_if/if2.rs

@@ -2,8 +2,10 @@
 fn picky_eater(food: &str) -> &str {
     if food == "strawberry" {
         "Yummy!"
+    } else if food == "potato" {
+        "I guess I can eat that."
     } else {
-        1
+        "No thanks!"
     }
 }
 

exercises/03_if/if3.rs

@@ -3,11 +3,11 @@ fn animal_habitat(animal: &str) -> &str {
     let identifier = if animal == "crab" {
         1
     } else if animal == "gopher" {
-        2.0
+        2
     } else if animal == "snake" {
         3
     } else {
-        "Unknown"
+        0
     };
 
     // Don't change the expression below!

exercises/04_primitive_types/primitive_types1.rs

@@ -8,7 +8,7 @@ fn main() {
 
     // TODO: Define a boolean variable with the name `is_evening` before the `if` statement below.
     // The value of the variable should be the negation (opposite) of `is_morning`.
-    // let …
+    let is_evening = !is_morning;
     if is_evening {
         println!("Good evening!");
     }

exercises/04_primitive_types/primitive_types2.rs

@@ -3,6 +3,7 @@
 fn main() {
     // Note the _single_ quotes, these are different from the double quotes
     // you've been seeing around.
+
     let my_first_initial = 'C';
     if my_first_initial.is_alphabetic() {
         println!("Alphabetical!");
@@ -16,7 +17,8 @@ fn main() {
     // below with your favorite character.
     // Try a letter, try a digit (in single quotes), try a special character, try a character
     // from a different language than your own, try an emoji 😉
-    // let your_character = '';
+
+    let your_character = '4';
 
     if your_character.is_alphabetic() {
         println!("Alphabetical!");

exercises/04_primitive_types/primitive_types3.rs

@@ -1,6 +1,6 @@
 fn main() {
     // TODO: Create an array called `a` with at least 100 elements in it.
-    // let a = ???
+    let a = [0; 100];
 
     if a.len() >= 100 {
         println!("Wow, that's a big array!");

exercises/04_primitive_types/primitive_types4.rs

@@ -9,7 +9,7 @@ mod tests {
         let a = [1, 2, 3, 4, 5];
 
         // TODO: Get a slice called `nice_slice` out of the array `a` so that the test passes.
-        // let nice_slice = ???
+        let nice_slice = &a[1..4];
 
         assert_eq!([2, 3, 4], nice_slice);
     }

exercises/04_primitive_types/primitive_types5.rs

@@ -4,5 +4,7 @@ fn main() {
     // TODO: Destructure the `cat` tuple in one statement so that the println works.
     // let /* your pattern here */ = cat;
 
+    let (name, age) = cat;
+
     println!("{name} is {age} years old");
 }

exercises/04_primitive_types/primitive_types6.rs

@@ -10,7 +10,7 @@ mod tests {
 
         // TODO: Use a tuple index to access the second element of `numbers`
         // and assign it to a variable called `second`.
-        // let second = ???;
+        let second = numbers.1;
 
         assert_eq!(second, 2, "This is not the 2nd number in the tuple!");
     }

exercises/05_vecs/vecs1.rs

@@ -3,7 +3,7 @@ fn array_and_vec() -> ([i32; 4], Vec<i32>) {
 
     // TODO: Create a vector called `v` which contains the exact same elements as in the array `a`.
     // Use the vector macro.
-    // let v = ???;
+    let v = vec![10, 20, 30, 40];
 
     (a, v)
 }

exercises/05_vecs/vecs2.rs

@@ -4,6 +4,7 @@ fn vec_loop(input: &[i32]) -> Vec<i32> {
     for element in input {
         // TODO: Multiply each element in the `input` slice by 2 and push it to
         // the `output` vector.
+        output.push(*element * 2);
     }
 
     output
@@ -21,12 +22,7 @@ fn vec_map(input: &[i32]) -> Vec<i32> {
     // by 2, but with iterator mapping instead of manually pushing into an empty
     // vector.
     // See the example in the function `vec_map_example` above.
-    input
+    input.iter().map(|element| element * 2).collect()
-        .iter()
-        .map(|element| {
-            // ???
-        })
-        .collect()
 }
 
 fn main() {

exercises/06_move_semantics/move_semantics1.rs

@@ -1,6 +1,6 @@
 // TODO: Fix the compiler error in this function.
 fn fill_vec(vec: Vec<i32>) -> Vec<i32> {
-    let vec = vec;
+    let mut vec = vec;
 
     vec.push(88);
 

exercises/06_move_semantics/move_semantics2.rs

@@ -20,7 +20,7 @@ mod tests {
     fn move_semantics2() {
         let vec0 = vec![22, 44, 66];
 
-        let vec1 = fill_vec(vec0);
+        let vec1 = fill_vec(vec0.clone());
 
         assert_eq!(vec0, [22, 44, 66]);
         assert_eq!(vec1, [22, 44, 66, 88]);

exercises/06_move_semantics/move_semantics3.rs

@@ -1,5 +1,5 @@
 // TODO: Fix the compiler error in the function without adding any new line.
-fn fill_vec(vec: Vec<i32>) -> Vec<i32> {
+fn fill_vec(mut vec: Vec<i32>) -> Vec<i32> {
     vec.push(88);
 
     vec

exercises/06_move_semantics/move_semantics4.rs

@@ -10,8 +10,8 @@ mod tests {
     fn move_semantics4() {
         let mut x = Vec::new();
         let y = &mut x;
-        let z = &mut x;
         y.push(42);
+        let z = &mut x;
         z.push(13);
         assert_eq!(x, [42, 13]);
     }

exercises/06_move_semantics/move_semantics5.rs

@@ -4,12 +4,12 @@
 // removing references (the character `&`).
 
 // Shouldn't 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();
 
     println!("{data}");
@@ -18,7 +18,7 @@ fn string_uppercase(mut data: &String) {
 fn main() {
     let data = "Rust is great!".to_string();
 
-    get_char(data);
+    get_char(&data);
 
-    string_uppercase(&data);
+    string_uppercase(data);
 }

exercises/07_structs/structs1.rs

@@ -1,9 +1,12 @@
 struct ColorRegularStruct {
     // TODO: Add the fields that the test `regular_structs` expects.
     // What types should the fields have? What are the minimum and maximum values for RGB colors?
+    red: u16,
+    green: u16,
+    blue: u16,
 }
 
-struct ColorTupleStruct(/* TODO: Add the fields that the test `tuple_structs` expects */);
+struct ColorTupleStruct(u16, u16, u16);
 
 #[derive(Debug)]
 struct UnitStruct;
@@ -19,7 +22,11 @@ mod tests {
     #[test]
     fn regular_structs() {
         // TODO: Instantiate a regular struct.
-        // let green =
+        let green = ColorRegularStruct {
+            red: 0,
+            green: 255,
+            blue: 0,
+        };
 
         assert_eq!(green.red, 0);
         assert_eq!(green.green, 255);
@@ -29,7 +36,7 @@ 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);
@@ -39,7 +46,7 @@ mod tests {
     #[test]
     fn unit_structs() {
         // TODO: Instantiate a unit struct.
-        // let unit_struct =
+        let unit_struct = UnitStruct;
         let message = format!("{unit_struct:?}s are fun!");
 
         assert_eq!(message, "UnitStructs are fun!");

exercises/07_structs/structs2.rs

@@ -34,7 +34,13 @@ mod tests {
         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: 2019,
+            item_number: 123,
+            count: 1,
+            ..order_template
+        };
 
         assert_eq!(your_order.name, "Hacker in Rust");
         assert_eq!(your_order.year, order_template.year);

exercises/quizzes/quiz1.rs

@@ -12,6 +12,10 @@
 // the quantity bought.
 // fn calculate_price_of_apples(???) -> ??? { ??? }
 
+fn calculate_price_of_apples(qty: u32) -> u32 {
+    if qty < 41 { qty * 2 } else { qty }
+}
+
 fn main() {
     // You can optionally experiment here.
 }