Variables

In Rust, variables are immutable by default. When a variable is immutable, once a value is bound to a name, you can’t change that value. You can make them mutable by adding mut in front of the variable name.

Further information

Rustlings

variables1

 
// variables1.rs
// Make me compile!
// Execute `rustlings hint variables1` or use the `hint` watch subcommand for a hint.

// I AM NOT DONE

fn main() {
    x = 5;
    println!("x has the value {}", x);
}

variables2

 
// variables2.rs
// Execute `rustlings hint variables2` or use the `hint` watch subcommand for a hint.

// I AM NOT DONE

fn main() {
    let x;
    if x == 10 {
        println!("x is ten!");
    } else {
        println!("x is not ten!");
    }
}

variables3

 
// variables3.rs
// Execute `rustlings hint variables3` or use the `hint` watch subcommand for a hint.

// I AM NOT DONE

fn main() {
    let x: i32;
    println!("Number {}", x);
}

variables4

 
// variables4.rs
// Execute `rustlings hint variables4` or use the `hint` watch subcommand for a hint.

// I AM NOT DONE

fn main() {
    let x = 3;
    println!("Number {}", x);
    x = 5; // don't change this line
    println!("Number {}", x);
}

variables5

 
// variables5.rs
// Execute `rustlings hint variables5` or use the `hint` watch subcommand for a hint.

// I AM NOT DONE

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

variables6

 
// variables6.rs
// Execute `rustlings hint variables6` or use the `hint` watch subcommand for a hint.

// I AM NOT DONE

const NUMBER = 3;
fn main() {
    println!("Number {}", NUMBER);
}