Working with Rust

Guessing Game in Rust

An example program of the classic guess a number between 1-100 game. This shows how to generate a rando number, gather user input, validate the result, and check against the guess.

Requires rand dependency in your Cargo.toml

Play with example in Rust Playground.

use rand::Rng;
use std::io;
use std::io::Write;
 
fn main() {
    // Set number, last number in range is not included so +1
    let x = rand::thread_rng().gen_range(1..101);
 
    // Track number of guesses
    let mut count = 1;
 
    // Prompt
    println!("Guess a number from 1-100:");
 
    loop {
        print!("Guess #{}: ", count);
        // Output gets flushed on new lines
        // To prompt on same line requires manual flush the output
        let _ = io::stdout().flush();
 
        // Get user input
        let mut input = String::new();
        io::stdin().read_line(&mut input).expect("User Input Error");
 
        // validate user input
        let guess = match input.trim().parse::<i32>() {
            Ok(x) => x,
            Err(_err) => {
                println!("  > Not a number. Try again");
                continue;
            }
        };
 
        if guess > x {
            println!(" > {} is too high", guess);
        }
        else if guess < x {
            println!(" > {} is too low", guess);
        }
        else {
            println!(" 🎉 Congrats! It was {}, it took {} guesses", guess, count);
            break;
        }
        count += 1;
    }
}