chore(rustlings): revise some rustlings exercises

Author: mmvanheusden

Other exercises/rustlings/01_variables/variables2.rs

@@ -5,7 +5,7 @@
 
 
 fn main() {
-    let x = 2;
+    let x = 1;
     if x == 10 {
         println!("x is ten!");
     } else {

Other exercises/rustlings/01_variables/variables5.rs

@@ -7,9 +7,6 @@
 fn main() {
     let number = "T-H-R-E-E"; // don't change this line
     println!("Spell a Number : {}", number);
-    {
-        let number = 3; // don't rename this variable
-        println!("Number plus two is : {}", number + 2);
-    }
-   
+    let number: i32 = 3; // don't rename this variable
+    println!("Number plus two is : {}", number + 2);
 }

Other exercises/rustlings/02_functions/functions1.rs

@@ -4,10 +4,10 @@
 // hint.
 
 
-fn call_me() {
-
-}
-
 fn main() {
     call_me();
 }
+
+fn call_me() {
+    println!("Call me maybe?");
+}

Other exercises/rustlings/02_functions/functions3.rs

@@ -5,7 +5,7 @@
 
 
 fn main() {
-    call_me(3);
+    call_me(2);
 }
 
 fn call_me(num: u32) {

Other exercises/rustlings/02_functions/functions4.rs

@@ -14,7 +14,7 @@ fn main() {
     println!("Your sale price is {}", sale_price(original_price));
 }
 
-fn sale_price(price: i32) -> i32 {
+fn sale_price(price: i32) -> i32{
     if is_even(price) {
         price - 10
     } else {

Other exercises/rustlings/03_if/if1.rs

@@ -5,10 +5,11 @@
 
 pub fn bigger(a: i32, b: i32) -> i32 {
     // 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 { return b; } else { return a; }
+    if b > a {b} else {a}
 }
 
 // Don't mind this for now :)

Other exercises/rustlings/03_if/if2.rs

@@ -11,7 +11,7 @@ pub fn foo_if_fizz(fizzish: &str) -> &str {
         "foo"
     } else if fizzish == "fuzz" {
         "bar"
-    } else { return "baz" }
+    } else {"baz"}
 }
 
 // No test changes needed!

Other exercises/rustlings/03_if/if3.rs

@@ -11,7 +11,7 @@ pub fn animal_habitat(animal: &str) -> &'static str {
     } else if animal == "snake" {
         3
     } else {
-        0
+        2222
     };
 
     // DO NOT CHANGE THIS STATEMENT BELOW

Other exercises/rustlings/04_primitive_types/primitive_types2.rs

@@ -18,7 +18,7 @@ fn main() {
         println!("Neither alphabetic nor numeric!");
     }
 
-    let your_character = 'Z'; // 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() {

Other exercises/rustlings/04_primitive_types/primitive_types3.rs

@@ -7,7 +7,7 @@
 
 
 fn main() {
-    let mut a = [999; 150];
+    let a = ["hello"; 120];
 
     if a.len() >= 100 {
         println!("Wow, that's a big array!");

Other exercises/rustlings/05_vecs/vecs1.rs

@@ -8,7 +8,6 @@
 // Execute `rustlings hint vecs1` or use the `hint` watch subcommand for a hint.
 
 
-
 fn array_and_vec() -> ([i32; 4], Vec<i32>) {
     let a = [10, 20, 30, 40]; // a plain array
     let v = vec![10,20,30,40]; // TODO: declare your vector here with the macro for vectors

Other exercises/rustlings/05_vecs/vecs2.rs

@@ -10,6 +10,8 @@
 
 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
     }
 
@@ -19,7 +21,9 @@ fn vec_loop(mut v: Vec<i32>) -> Vec<i32> {
 
 fn vec_map(v: &Vec<i32>) -> Vec<i32> {
     v.iter().map(|element| {
-        element * 2
+        // TODO: Do the same thing as above - but instead of mutating the
+        // Vec, you can just return the new number!
+        *element * 2
     }).collect()
 }
 

Other exercises/rustlings/06_move_semantics/move_semantics2.rs

@@ -10,7 +10,7 @@
 fn main() {
     let vec0 = vec![22, 44, 66];
 
-    let mut vec1 = fill_vec(vec0.clone());
+    let vec1 = fill_vec(vec0.clone());
 
     assert_eq!(vec0, vec![22, 44, 66]);
     assert_eq!(vec1, vec![22, 44, 66, 88]);

Other exercises/rustlings/06_move_semantics/move_semantics3.rs

@@ -11,7 +11,7 @@
 fn main() {
     let vec0 = vec![22, 44, 66];
 
-    let mut vec1 = fill_vec(vec0);
+    let vec1 = fill_vec(vec0);
 
     assert_eq!(vec1, vec![22, 44, 66, 88]);
 }

Other exercises/rustlings/06_move_semantics/move_semantics4.rs

@@ -12,18 +12,16 @@
 fn main() {
     let vec0 = vec![22, 44, 66];
 
-    let mut vec1 = fill_vec();
+    let vec1 = fill_vec();
 
     assert_eq!(vec1, vec![22, 44, 66, 88]);
 }
 
 // `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![];
-    vec.push(22);
-    vec.push(44);
-    vec.push(66);
+    let mut vec = vec![22,44,66];
+
     vec.push(88);
 
     vec

Other exercises/rustlings/06_move_semantics/move_semantics6.rs

@@ -23,5 +23,5 @@ fn get_char(data: &String) -> char {
 fn string_uppercase(mut data: String) {
     data = data.to_uppercase();
 
-    println!("{}", &data);
+    println!("{}", data);
 }

Other exercises/rustlings/07_structs/structs1.rs

@@ -7,29 +7,26 @@
 
 
 struct ColorClassicStruct {
-    red: i32,
-    green: i32,
-    blue: i32,
+    red: u8,
+    green: u8,
+    blue: u8
 }
 
-
-struct ColorTupleStruct(
-    i32,i32,i32 // can't give 'em names
-);
+struct ColorTupleStruct(u8,u8,u8);
 
 #[derive(Debug)]
 struct UnitLikeStruct;
 
-
-
 #[cfg(test)]
 mod tests {
     use super::*;
 
     #[test]
     fn classic_c_structs() {
         let green = ColorClassicStruct {
-            red: 0,green: 255,blue: 0
+            red: 0,
+            green: 255,
+            blue: 0
         };
 
         assert_eq!(green.red, 0);
@@ -40,15 +37,16 @@ mod tests {
     #[test]
     fn tuple_structs() {
         let green = ColorTupleStruct(0,255,0);
-
+        
         assert_eq!(green.0, 0);
         assert_eq!(green.1, 255);
         assert_eq!(green.2, 0);
     }
 
     #[test]
     fn unit_structs() {
-        let message = format!("{:?}s are fun!", UnitLikeStruct);
+        let unit_like_struct = UnitLikeStruct;
+        let message = format!("{:?}s are fun!", unit_like_struct);
 
         assert_eq!(message, "UnitLikeStructs are fun!");
     }

Other exercises/rustlings/07_structs/structs2.rs

@@ -36,6 +36,7 @@ mod tests {
     #[test]
     fn your_order() {
         let order_template = create_order_template();
+        // TODO: Create your own order using the update syntax and template above!
         let your_order = Order {
             name: "Hacker in Rust".to_string(),
             count: 1,

Other exercises/rustlings/07_structs/structs3.rs

@@ -31,12 +31,11 @@ impl Package {
     }
 
     fn is_international(&self) -> bool {
-        !(self.sender_country == self.recipient_country)
+        self.recipient_country != self.sender_country
     }
 
     fn get_fees(&self, cents_per_gram: u32) -> u32 {
-        // Something goes here...
-        self.weight_in_grams * cents_per_gram
+        cents_per_gram * self.weight_in_grams
     }
 }
 

Other exercises/rustlings/08_enums/enums1.rs

@@ -5,10 +5,11 @@
 
 #[derive(Debug)]
 enum Message {
+    // TODO: define a few types of messages as used below
     Quit,
     Echo,
     Move,
-    ChangeColor,
+    ChangeColor
 }
 
 fn main() {