Variables and Mutability in Rust

Snippet

Variables and Mutability in Rust

In Rust, variables are immutable by default. This means once you assign a value to a variable, you cannot change it. This is a powerful feature that helps prevent bugs. If you need to change a variable's value, you must declare it with the 'mut' keyword. This explicit mutability makes code safer and easier to reason about.

snippet.rs
rust
fn main() {
    let x = 5;
    let mut y = 10;
    
    println!("x = {}, y = {}", x, y);
    
    y = 15;
    // x = 6; // This would fail - x is immutable
    
    println!("y = {}", y);
}

Breakdown

let x = 5;

Creates an immutable variable x with value 5

let mut y = 10;

Creates a mutable variable y with value 10

y = 15;

Successfully changes y to 15 because y is mutable

Previous snippet Next snippet

From your library

Variables and Mutability in Rust

Related