diff --git a/en/src/variables.md b/en/src/variables.md index ee92711..e638876 100644 --- a/en/src/variables.md +++ b/en/src/variables.md @@ -1,9 +1,10 @@ # Variables ### Binding and mutablity -🌟 fix the error below with least modifying +🌟 A variable can be used only if it has been initialized. ```rust,editable +// fix the error below with least modifying fn main() { let x: i32; // uninitialized but using, ERROR ! let y: i32; // uninitialized but also unusing, only warning @@ -11,11 +12,11 @@ fn main() { } ``` -🌟🌟 fill the blanks in code to make it compile +🌟 Use `mut` to mark a variable as mutable. ```rust,editable +// fill the blanks in code to make it compile fn main() { - // replace __ with a variable name let __ = 1; __ += 2; @@ -24,9 +25,10 @@ fn main() { ``` ### Scope -🌟 fix the error below with least modifying +🌟 A scope is the range within the program for which the item is valid. ```rust,editable +// fix the error below with least modifying fn main() { let x: i32 = 10; { @@ -37,9 +39,10 @@ fn main() { } ``` -🌟🌟 fix the error with the knowledge you grasped +🌟🌟 ```rust,editable +// fix the error fn main() { println!("{}, world", x); } @@ -50,10 +53,11 @@ fn define_x() { ``` ### Shadowing -🌟🌟 only modify `assert_eq!` to make the `println!` work(print `42` in terminal) +🌟🌟 You can declare a new variable with the same name as a previous variable, here we can say **the first one is shadowed by the second one. ```rust,editable +// only modify `assert_eq!` to make the `println!` work(print `42` in terminal) fn main() { let x: i32 = 5; {