闲得无聊，便想用rust来写写进度条的实现，参考来网上c语言版本的实现，遂用rust也写了一个。 废话不多说， 直接上代码：

use std::thread::sleep;
use std::time::Duration;
use std::io::prelude::*;
use std::io::{self, BufWriter, Write};

fn progress1(){
    let mut _str: [char;101] = [' ';101];
    let nchar:[char;4] = ['-','\\', '|', '/',];
    let mut sw = BufWriter::new(io::stdout());
    for progress_v in 0..=100usize{
        // 注意 /r xxxx 和 xxxx /r的区别： 前者是先定位到行头再输出xxxx， 后者则是先输出xxxx，再定位到行头。
        // 前者再mac osx上能正确地看到输出，后者则一直不显示输出。
        sw.write_fmt(format_args!("\r{}",'['));
        _str[progress_v] = '#';
        for i in _str.iter(){
            sw.write_fmt(format_args!("{}", i));
        }
        sw.write_fmt(format_args!("{}", ']'));
        let _ = sw.write_fmt(format_args!("\t({:3}%)\t[{}]", progress_v, nchar[progress_v % 4]));
        sw.flush();
        sleep(Duration::from_millis(400));
    }
}

fn main() {
    progress1();
}