如何在C ++中从命令行中删除打印字符 [英] How to delete printed characters from command line in C++

问题描述

我是下载一个编译器（我认为是MinGW，但我不确定）在Windows 2000的另一天（我一般是一个Mac用户，但它不是我的机器），下载是一个MS-DOS命令行应用程序，将显示下载的进度条。这样的东西...

I was downloading a compiler (I think it was MinGW but I'm not sure) on windows 2000 the other day (I'm generally a Mac user, but it wasn't my machine), and the downloader was a MS-DOS command line app that would display a progress bar for the download. Something like this...

|---                 | 15%
...
|------              | 30%
...
...
|--------------      | 70%

，除了它将在同一行上连续更新。我假设程序通过删除以前打印的字符并重新打印不同的字符，但我似乎不知道如何做到这一点。

except that it would continuously update on the same line. I assume the program accomplished this by deleting previously printed characters and reprinting different ones, but I can't seem to figure out how to do this.

我已经尝试打印一个'删除'字符若干不同的方式，如（char）8 和 \b $ c> \r ，我听说回到一些语言的开头行），但这些都没有效果。

I've tried to print a 'delete' character several different ways, like (char)8 and \b (even \r, which I heard backtracks to the beginning of the line in some languages), but none of those things worked.

有人知道如何做这样的东西吗？

Does anyone know how to do this sort of stuff?

编辑：这个问题已经成为平台特定。我想知道如何在Mac上完成这个。

This question has become platform-specific. I want to know specifically how to accomplish this on a Mac.

推荐答案

我不知道为什么你遇到问题，可以使用'\ b 或 \r`来执行此操作。

I'm not sure why you ran into problems, but either '\bor\r` can be used to do this.

#include <iostream>
#include <iomanip>
#include <string>
#include <windows.h>

// This is the only non-portable part of this code.
// Simply pause for a specified number of milliseconds
// For Windows, we just call Sleep. For Linux, you'd
// probably call nanosleep instead (with a suitable
// multiplier, of course). Most other systems (presumably)
// have (at least vaguely) similar capabilities.
void pause(int ms) { 
    Sleep(ms);
}

static const int width = 40;    

void show_percent(int i) {
     int dashes = (width * i)/100;

     std::cout << '|' << std::left << std::setw(width) << std::string(dashes, '-') << '|' << std::setw(3) << i << "%";
}

int main() {

    for (int i=0; i<101; i++) {
        show_percent(i);
        std::cout << std::string(width+6, '\b');
        pause(100);
    }
}

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