complete exercise variables

exercises/01_variables/variables1.rs

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

exercises/01_variables/variables2.rs

@@ -1,6 +1,6 @@
 fn main() {
     // TODO: Change the line below to fix the compiler error.
-    let x;
+    let x = 10;
 
     if x == 10 {
         println!("x is ten!");

exercises/01_variables/variables3.rs

@@ -1,6 +1,6 @@
 fn main() {
     // TODO: Change the line below to fix the compiler error.
-    let x: i32;
+    let x: i32 = 9;
 
     println!("Number {x}");
 }

exercises/01_variables/variables4.rs

@@ -1,6 +1,6 @@
 // TODO: Fix the compiler error.
 fn main() {
-    let x = 3;
+    let mut x = 3;
     println!("Number {x}");
 
     x = 5; // Don't change this line

exercises/01_variables/variables5.rs

@@ -3,6 +3,6 @@ fn main() {
     println!("Spell a number: {number}");
 
     // TODO: Fix the compiler error by changing the line below without renaming the variable.
-    number = 3;
+    let number = 3;
     println!("Number plus two is: {}", number + 2);
 }

exercises/01_variables/variables6.rs

@@ -1,5 +1,5 @@
 // TODO: Change the line below to fix the compiler error.
-const NUMBER = 3;
+const NUMBER: i32 = 3;
 
 fn main() {
     println!("Number: {NUMBER}");