GuessGame

基础

声明变量

静态方法使用 ::

let foo = 5; // 不可变 
let mut bar = 5; // 可变
let mut guess = String::new();

输入

不写expect捕获异常会有警告，& 表示这是一个引用

use std::io;
// ...other code

io::stdin().read_line(&mut guess)
  .expect("Failed to read line");

安装依赖

在 Cargo.toml 下的 [dependencies] 添加 rand = "0.3.14"，然后使用 cargo build

更新依赖

cargo update

引入外部依赖

extern crate rand;
// 自动调用 use rand

最终代码

extern crate rand;
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, 101);
    println!("The secret number is: {}", secret_number);
    loop {
        println!("Please input your guess.");
        let mut guess = String::new();
        io::stdin()
            .read_line(&mut guess)
            .expect("Failed to read line");
        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;
            }
        }
    }
}