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Variables in Rust

Variables are used to store data in memory.

In Rust, variables are immutable by default, which means their values cannot be changed after creation.

Declaring a Variable​

fn main() {
    let x = 10;
    println!("{}", x);
}

Explanation​

  • let is used to declare a variable.
  • x is the variable name.
  • 10 is the value stored in the variable.
  • println!() prints the value.

Immutable Variables​

fn main() {
    let x = 5;
    // x = 6; ❌ Error
}

Rust does not allow changing immutable variables.

Mutable Variables​

To make a variable changeable, use mut.

fn main() {
    let mut x = 5;
    x = 10;

    println!("{}", x);
}

Explanation​

  • mut means mutable.
  • Mutable variables can change their values.

Variable Shadowing​

Rust allows redeclaring variables using the same name.

fn main() {
    let x = 5;
    let x = x + 1;

    println!("{}", x);
}

Output​

6

Shadowing creates a new variable with the same name.