Variables in Rust

In this tutorial, we will learn about variables in Rust. We will cover the basics of declaring and using variables, including naming conventions.

What are Variables

Variables in Rust are used to store data values that can be manipulated during program execution. Rust is a statically typed language, meaning the data type of a variable is known at compile time.

Naming Variables

When naming variables in Rust, follow these conventions:

  • Variable names must start with a letter or an underscore (_).
  • Subsequent characters can include letters, digits, and underscores.
  • Variable names are case-sensitive.
  • Avoid using reserved keywords as variable names.
  • Use snake_case naming convention for readability.

Syntax

The syntax to declare variables in Rust is:

let variable_name = value;
let mut variable_name = value; // for mutable variables

Example 1: Variable storing Integer Value

  1. Declare an integer variable named num.
  2. Assign a value of 10 to the variable.
  3. Print the value of the variable.

Rust Program

fn main() {
    let num = 10;
    println!("The value of num is: {}", num);
}

Output

The value of num is: 10

Example 2: Variable storing String Value

  1. Declare a string variable named name.
  2. Assign the value 'John' to the variable.
  3. Print the value of the variable.

Rust Program

fn main() {
    let name = "John";
    println!("The value of name is: {}", name);
}

Output

The value of name is: John

Example 3: Variable storing Boolean Value

  1. Declare a boolean variable named is_true.
  2. Assign the value true to the variable.
  3. Print the value of the variable.

Rust Program

fn main() {
    let is_true = true;
    println!("The value of is_true is: {}", is_true);
}

Output

The value of is_true is: true