rust - Rust 1.3.0 中的猜谜游戏

Question

猜谜游戏的问题

extern crate rand;

use std::io;

use std::cmp::Ordering;

use rand::Rng;



fn main() {

    println!("Guess the number!");

    let secret_number = rand::thread_rng().gen_range(1, 101);


    println!("The secret number is: {}", secret_number);

    println!("Please input your guess.");

    let mut guess = String::new();

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

    println!("You guessed: {}", guess);

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

但这给我一个错误:

src\main.rs:26:21: 26:35 error: mismatched types:
 expected `&collections::string::String`,
    found `&_`
(expected struct `collections::string::String`,
    found integral variable) [E0308]
src\main.rs:26     match guess.cmp(&secret_number) {
                                   ^~~~~~~~~~~~~~

这是什么原因造成的，我该如何解决？

Answer 1

来自 stdin 的用户输入是一个字符串。而你从 rand 得到的数字是 u32。尝试在 secret_number 上使用 to_string。

匹配猜测.cmp(&secret_number.to_string())