Variables and Constants

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Variable

In Rust, we declare variables first and initialize them later. In Rust, variables are declared by let keyword followed by the variable name that you simply wish to declare.
In Rust, variables are immutable by default. This is just one of the numerous suggestions Rust makes to help you build code that takes advantage of Rust's safety and complexity..

let <name> : <type>;

let <name> = <value>

fn main() {
    let mut x = 45; // i32

    let y: i64 = 81; //i64

    // floating point numbers 
    let _f: f32 = 6.7;
    

    let _b: bool = false;

    println!("y: {}", y);
    println!("The value of x is {}", x);

    x = 60;

    println!("The value of x is {}", x);

}

Constants

Constants are non-changeable literals whose values cannot be changed at the time of execution of the program.

const <name> = <value>;

By convention, constant names are always preferred in uppercase.

Shadowing

Shadowing is a concept in which we can re-declare and reuse the same variable in the same scope.

It can be reassigned with a new type and value. The variable name in the following example is declared. This variable has been renamed and a new value has been assigned to it.

Example:

fn main() {
    let x = 12;

    {
        let x = 15;
        println!("value of x is {}", x);
    }

    let x = 13;
    println!("value of x is {}", x);

    let x = "Yaman";
    println!("value of x is {}", x);
}

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Rust Tutorials | Projects | Interview Questions Tutorial

Rust Tutorials | Projects | Interview Questions Tutorial

Variables and Constants

Variable

Constants

Shadowing

Important Links

Rust Tutorials | Projects | Interview Questions Tutorial

Rust Tutorials | Projects | Interview Questions Tutorial

Introduction

Variables and Constants

Variable

Constants

Shadowing

Important Links