The rand crate provides us plenty of ways to generate random numbers. Here are a few examples:

Generate a random integer that fits in an i8

let random_i8: i8 = rand::random();

Generate random floating point that fits in an f32

let random_f32: f32 = rand::random();

Generate a random boolean

We can even ask it to generate a true or false randomly.

let random_bool: bool = rand::random();

Generate a random whole number in a range

For this we need to load the rand::Rng

use rand::Rng;

let random_number = rand::thread_rng().gen_range(1..=100);

Dependency

examples/generate-random-numbers/Cargo.toml

[package]
name = "generate-random-numbers"
version = "0.1.0"
edition = "2021"

# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html

[dependencies]
rand = "0.8.5"

Code

examples/generate-random-numbers/src/main.rs

use rand::Rng;

fn main() {
    let random_i8: i8 = rand::random();
    println!("random_i8: {random_i8}");

    let random_f32: f32 = rand::random();
    println!("random_f32: {random_f32}");

    let random_bool: bool = rand::random();
    println!("random_bool: {random_bool}");

    let random_number = rand::thread_rng().gen_range(1..=100);
    println!("random_number: {random_number}");
}

Running the code

$ cargo run -q
random_i8: 47
random_f32: 0.69342864
random_bool: false
random_number: 54

$ cargo run -q
random_i8: 46
random_f32: 0.063155234
random_bool: false
random_number: 31