Merge pull request #1 from ZhiHanZ/exercise_ans

Exercise ans

exercises/functions/functions1.rs

@@ -1,8 +1,10 @@
 // functions1.rs
 // Make me compile! Execute `rustlings hint functions1` for hints :)
 
-// I AM NOT DONE
 
 fn main() {
     call_me();
 }
+fn call_me(){
+    println!("do that is what you want?");
+}

exercises/functions/functions2.rs

@@ -1,13 +1,12 @@
 // functions2.rs
 // Make me compile! Execute `rustlings hint functions2` for hints :)
 
-// I AM NOT DONE
 
 fn main() {
     call_me(3);
 }
 
-fn call_me(num) {
+fn call_me(num : i32) {
     for i in 0..num {
         println!("Ring! Call number {}", i + 1);
     }

exercises/functions/functions3.rs

@@ -1,10 +1,9 @@
 // functions3.rs
 // Make me compile! Execute `rustlings hint functions3` for hints :)
 
-// I AM NOT DONE
 
 fn main() {
-    call_me();
+    call_me(3);
 }
 
 fn call_me(num: i32) {

exercises/functions/functions4.rs

@@ -4,18 +4,17 @@
 // 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.
 
-// I AM NOT DONE
 
 fn main() {
-    let original_price = 51;
+    let original_price = 1;
     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
+        price - 10 // no semicolon means a return value
     } else {
-        price - 3
+        return price - 3; // java style is fine
     }
 }
 

exercises/functions/functions5.rs

@@ -1,7 +1,6 @@
 // functions5.rs
 // Make me compile! Execute `rustlings hint functions5` for hints :)
 
-// I AM NOT DONE
 
 fn main() {
     let answer = square(3);
@@ -9,5 +8,5 @@ fn main() {
 }
 
 fn square(num: i32) -> i32 {
-    num * num;
+    num * num // again semicolon should not be used in return 
 }

exercises/if/if1.rs

@@ -1,6 +1,5 @@
 // if1.rs
 
-// I AM NOT DONE
 
 pub fn bigger(a: i32, b: i32) -> i32 {
     // Complete this function to return the bigger number!
@@ -8,6 +7,7 @@ pub fn bigger(a: i32, b: i32) -> i32 {
     // - another function call
     // - additional variables
     // Execute `rustlings hint if1` for hints
+    return if a > b {a} else {b}
 }
 
 // Don't mind this for now :)

exercises/test1.rs

@@ -7,7 +7,6 @@
 // more than 40 at once, each apple only costs 1! Write a function that calculates
 // the price of an order of apples given the order amount. No hints this time!
 
-// I AM NOT DONE
 
 // Put your function here!
 // fn ..... {
@@ -21,3 +20,6 @@ fn verify_test() {
     assert_eq!(70, price1);
     assert_eq!(65, price2);
 }
+fn calculate_apple_price(number : i32) -> i32{
+    if number > 40 {number * 1} else {number * 2}
+}

exercises/variables/variables1.rs

@@ -6,9 +6,8 @@
 // even after you already figured it out. If you got everything working and
 // feel ready for the next exercise, remove the `I AM NOT DONE` comment below.
 
-// I AM NOT DONE
 
 fn main() {
-    x = 5;
+    let x = 5;
     println!("x has the value {}", x);
 }

exercises/variables/variables2.rs

@@ -1,10 +1,9 @@
 // variables2.rs
 // Make me compile! Execute the command `rustlings hint variables2` if you want a hint :)
 
-// I AM NOT DONE
 
 fn main() {
-    let x;
+    let x = 10;
     if x == 10 {
         println!("Ten!");
     } else {

exercises/variables/variables3.rs

@@ -1,11 +1,10 @@
 // variables3.rs
 // Make me compile! Execute the command `rustlings hint variables3` if you want a hint :)
 
-// I AM NOT DONE
 
 fn main() {
     let x = 3;
     println!("Number {}", x);
-    x = 5;
+    let x = 5; // shadowing
     println!("Number {}", x);
 }

exercises/variables/variables4.rs

@@ -1,9 +1,8 @@
 // variables4.rs
 // Make me compile! Execute the command `rustlings hint variables4` if you want a hint :)
 
-// I AM NOT DONE
 
 fn main() {
-    let x: i32;
+    let x: i32 = 0;// initilization is mandatory for compiler
     println!("Number {}", x);
 }

exercises/variables/variables5.rs

@@ -1,11 +1,9 @@
 // variables5.rs
 // Make me compile! Execute the command `rustlings hint variables5` if you want a hint :)
 
-// I AM NOT DONE
-
 fn main() {
-    let number = "3";
+    let number = "3"; // shadowing can init val with diff type
     println!("Number {}", number);
-    number = 3;
+    let number = 3;
     println!("Number {}", number);
 }