如何制作“进度条"使用printf? [英] How to make a "progress bar" using printf?

问题描述

许多命令行工具实现了基于文本的进度条.喜欢rpm安装:

<块引用>

安装##############[45%]

# 随百分比增长，同时保持在一行.我想要的是类似的东西:我需要一个只占用一行的进度指示器，也就是说，当百分比增长时，它会被覆盖，而不是创建一个新行(\n).>

我试过了:

 #include 国际主要(){int i = 0;对于 (i = 0; i <10000; i++){printf("\r正在进行 %d", i/100);}printf("\n");}

\r 用于覆盖单行.但是，\r 将光标移至行首，printf 将光标移至行尾，导致光标快速摆动.大家稍微编译一下就可以感受到了.任何人都可以想出替代方法来避免这个问题吗?

解决方案

这是缓冲 stdout 流的问题.您必须在 printf() 之后使用 fflush(stdout) 显式刷新它(使用 \n 进行隐式刷新):

fflush(stdout);

Many command line tools implement text-based progress bar. Like rpm installing:

installing ##############[45%]

the # grows with the percentage, while keeps itself in a single line. What I want is something similar: I need a progress indicator taking just one line, that is to say, when percentage grows, it got overwritten, instead of make a new line(\n).

I tried this:

   #include <stdio.h>

   int main (){
       int i = 0;
       for (i = 0; i < 10000; i++){
           printf("\rIn progress %d", i/100);
       }
       printf("\n");
   }

\r works to overwrite the single line. However, \r brings cursor to the beginning of line and printf brings cursor to the end, which result in a rapidly waving cursor. You guys can feel it by a little compiling. Can Anyone come up with alternatives to avoid this issue?

解决方案

This is a problem of the stdout stream being buffered. You have to flush it explicitly (implicit flushing occurs with a \n) using fflush(stdout) after the printf():

fflush(stdout);

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