Integer types in Rust

Introduction

Integer types let you store whole numbers in your program. They help you work with counts, ages, or any number without fractions.

Counting items like apples or books

Storing ages or years

Working with indexes in a list

Representing simple scores or points

Syntax

Rust

let variable_name: integer_type = value;

Integer types in Rust include signed (can be negative) and unsigned (only positive) numbers.

Common types: i8, i16, i32, i64, i128 (signed) and u8, u16, u32, u64, u128 (unsigned).

Examples

This creates a signed 32-bit integer named age with value 30.

Rust

let age: i32 = 30;

This creates an unsigned 8-bit integer named count with the max value 255.

Rust

let count: u8 = 255;

This creates a signed 16-bit integer named temperature with a negative value.

Rust

let temperature: i16 = -10;

Sample Program

This program stores counts of fruits using unsigned integers and a temperature using a signed integer. It then prints the results.

Rust

fn main() {
    let apples: u8 = 10;
    let oranges: u8 = 20;
    let total_fruits: u8 = apples + oranges;
    println!("Total fruits: {}", total_fruits);

    let temperature: i32 = -5;
    println!("Temperature: {} degrees", temperature);
}

Important Notes

Use signed integers (i8, i16, etc.) when you need negative numbers.

Use unsigned integers (u8, u16, etc.) when you only need zero or positive numbers.

Choosing the right size (8, 16, 32, 64, 128) depends on how big your numbers can get.

Summary

Integer types store whole numbers without decimals.

Signed integers can be negative; unsigned cannot.

Pick the size and sign based on your number needs.