Rust学习——猜猜看游戏

猜猜看游戏

use rand::Rng;
use std::cmp::Ordering;
use std::io;
fn main() {
    println!("Guess the number!");

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

    // println!("The secret number is: {}", secret_number);
    //  loop 关键字创建了一个无限循环
    loop {
        println!("Please input your guess.");
        let mut guess = String::new();
        //  std::io::stdin stdin 函数返回一个 std::io::Stdin 的实例，这代表终端标准输入句柄的类型 调用 read_line 方法从标准输入句柄获取用户输入
        io::stdin()
            .read_line(&mut guess)
            .expect("Failed to read line");

        // String 实例的 trim 方法会去除字符串开头和结尾的空白字符 字符串的 parse 方法 将字符串转换成其他类型
        // let guess: u32 = guess.trim().parse().expect("Please type a number!");
        let guess: u32 = match guess.trim().parse() {
            Ok(num) => num,
            Err(_) => continue,
        };
        println!("You guessed:{guess}");

        match guess.cmp(&secret_number) {
            Ordering::Less => println!("Too small!"),
            Ordering::Greater => println!("Too big!"),
            Ordering::Equal => {
                println!("You win!");
                break;
            }
        }
    }
}