如何从输入中读取单个字符作为u8? [英] How to read a single character from input as u8?

问题描述

我目前正在为此语言构建一个简单的解释器以进行练习.剩下要克服的唯一问题是从用户输入中读取单个字节作为字符.到目前为止，我有以下代码，但是我需要一种方法将第二行中的String转换为u8或我可以转换的另一个整数:

I am currently building a simple interpreter for this language for practice. The only problem left to overcome is reading a single byte as a character from user input. I have the following code so far, but I need a way to turn the String that the second lines makes into a u8 or another integer that I can cast:

let input = String::new()
let string = std::io::stdin().read_line(&mut input).ok().expect("Failed to read line");
let bytes = string.chars().nth(0) // Turn this to byte?

以字节为单位的值应该是u8，我可以将其强制转换为i32以便在其他地方使用.也许有一种更简单的方法可以做到这一点，否则我将使用任何可行的解决方案.

The value in bytes should be a u8 which I can cast to a i32 to use elsewhere. Perhaps there is a simpler way to do this, otherwise I will use any solution that works.

推荐答案

仅读取一个字节并将其强制转换为i32:

Reading just a byte and casting it to i32:

use std::io::Read;

let input: Option<i32> = std::io::stdin()
    .bytes() 
    .next()
    .and_then(|result| result.ok())
    .map(|byte| byte as i32);

println!("{:?}", input);

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