Rust Mutable

Rust mutable

Created By: chatGPT

In Rust, a variable is immutable by default. To make a variable mutable, you need to use the mut keyword. This allows you to change the value of the variable after it has been initialized. Here's an example:

fn main() {
    let mut x = 5; // x is mutable
    println!("Value of x: {}", x);
    x = 10; // x can be changed
    println!("New value of x: {}", x);
}

In this snippet, we declare a mutable variable x and reassign its value later. If you tried to reassign an immutable variable, the compiler would throw an error.

fn main() {
    let y = 5; // y is immutable
    println!("Value of y: {}", y);
    // y = 10; // This would cause an error!
}

Mutability can also apply to data structures, such as arrays or vectors. For example, you can have a mutable vector and change its contents:

fn main() {
    let mut vec = vec![1, 2, 3]; // mutable vector
    println!("Vector before: {:?}", vec);
    vec.push(4); // push a new value
    println!("Vector after: {:?}", vec);
}

Keep in mind that mutability is scoped. Even if a variable is declared as mutable, it will only be mutable within its scope. After leaving its scope, it cannot be modified.

fn main() {
    let mut z = 5;
    {
        z += 1; // This works
    }
    // z = z + 1; // Still works
}