93

我正在用 C++ 编写一个控制台程序来下载一个大文件。我知道文件大小，我启动了一个工作线程来下载它。我想显示一个进度指示器，让它看起来更酷。

如何在 cout 或 printf 中在不同时间但在同一位置显示不同的字符串？

4

9 回答 9

118

With a fixed width of your output, use something like the following:

float progress = 0.0;
while (progress < 1.0) {
    int barWidth = 70;

    std::cout << "[";
    int pos = barWidth * progress;
    for (int i = 0; i < barWidth; ++i) {
        if (i < pos) std::cout << "=";
        else if (i == pos) std::cout << ">";
        else std::cout << " ";
    }
    std::cout << "] " << int(progress * 100.0) << " %\r";
    std::cout.flush();

    progress += 0.16; // for demonstration only
}
std::cout << std::endl;

http://ideone.com/Yg8NKj

[>                                                                     ] 0 %
[===========>                                                          ] 15 %
[======================>                                               ] 31 %
[=================================>                                    ] 47 %
[============================================>                         ] 63 %
[========================================================>             ] 80 %
[===================================================================>  ] 96 %

Note that this output is shown one line below each other, but in a terminal emulator (I think also in Windows command line) it will be printed on the same line.

At the very end, don't forget to print a newline before printing more stuff.

If you want to remove the bar at the end, you have to overwrite it with spaces, to print something shorter like for example "Done.".

Also, the same can of course be done using printf in C; adapting the code above should be straight-forward.

于 2013-01-26T18:11:11.070 回答
61

您可以使用没有换行符 (\n) 的“回车”(\r)，并希望您的控制台做正确的事情。

于 2013-01-26T18:05:55.227 回答
55

对于C具有可调节进度条宽度的解决方案，您可以使用以下内容：

#define PBSTR "||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||"
#define PBWIDTH 60

void printProgress(double percentage) {
    int val = (int) (percentage * 100);
    int lpad = (int) (percentage * PBWIDTH);
    int rpad = PBWIDTH - lpad;
    printf("\r%3d%% [%.*s%*s]", val, lpad, PBSTR, rpad, "");
    fflush(stdout);
}

它将输出如下内容：

 75% [||||||||||||||||||||||||||||||||||||||||||               ]
于 2016-03-30T17:33:36.927 回答
14

看看 boost progress_display

http://www.boost.org/doc/libs/1_52_0/libs/timer/doc/original_timer.html#Class%20progress_display

我认为它可能会满足您的需求，并且我相信它只是一个标头库，因此无需链接

于 2013-01-26T21:28:05.917 回答
12

您可以打印回车符 ( \r) 以将输出“光标”移回当前行的开头。

对于更复杂的方法，请查看 ncurses（基于控制台文本的界面的 API）之类的东西。

于 2013-01-26T18:05:41.957 回答
6

我知道我回答这个问题有点晚了，但我做了一个简单的课程，完全符合你的要求。（请记住，我using namespace std;在此之前写过。）：

class pBar {
public:
    void update(double newProgress) {
        currentProgress += newProgress;
        amountOfFiller = (int)((currentProgress / neededProgress)*(double)pBarLength);
    }
    void print() {
        currUpdateVal %= pBarUpdater.length();
        cout << "\r" //Bring cursor to start of line
            << firstPartOfpBar; //Print out first part of pBar
        for (int a = 0; a < amountOfFiller; a++) { //Print out current progress
            cout << pBarFiller;
        }
        cout << pBarUpdater[currUpdateVal];
        for (int b = 0; b < pBarLength - amountOfFiller; b++) { //Print out spaces
            cout << " ";
        }
        cout << lastPartOfpBar //Print out last part of progress bar
            << " (" << (int)(100*(currentProgress/neededProgress)) << "%)" //This just prints out the percent
            << flush;
        currUpdateVal += 1;
    }
    std::string firstPartOfpBar = "[", //Change these at will (that is why I made them public)
        lastPartOfpBar = "]",
        pBarFiller = "|",
        pBarUpdater = "/-\\|";
private:
    int amountOfFiller,
        pBarLength = 50, //I would recommend NOT changing this
        currUpdateVal = 0; //Do not change
    double currentProgress = 0, //Do not change
        neededProgress = 100; //I would recommend NOT changing this
};

如何使用的示例：

int main() {
    //Setup:
    pBar bar;
    //Main loop:
    for (int i = 0; i < 100; i++) { //This can be any loop, but I just made this as an example
        //Update pBar:
        bar.update(1); //How much new progress was added (only needed when new progress was added)
        //Print pBar:
        bar.print(); //This should be called more frequently than it is in this demo (you'll have to see what looks best for your program)
        sleep(1);
    }
    cout << endl;
    return 0;
}

注意：我公开了所有类的字符串，以便可以轻松更改栏的外观。

于 2016-03-20T19:42:30.820 回答
5

另一种方法可能是显示“点”或您想要的任何字符。下面的代码将每隔 1 秒将进度指示器 [加载的排序...] 打印为点。

PS：我在这里使用睡眠。如果担心性能，请三思。

#include<iostream>
using namespace std;
int main()
{
    int count = 0;
    cout << "Will load in 10 Sec " << endl << "Loading ";
    for(count;count < 10; ++count){
        cout << ". " ;
        fflush(stdout);
        sleep(1);
    }
    cout << endl << "Done" <<endl;
    return 0;
}
于 2015-02-27T14:00:20.857 回答
2

这是我做的一个简单的：

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

using namespace std;

int barl = 20;

int main() {
   system("color 0e");  
   cout << "[";     
   for (int i = 0; i < barl; i++) {         
      Sleep(100);       
      cout << ":";  
   }
   cout << "]";
}
于 2017-12-24T10:30:54.510 回答
0

可能这段代码会帮助你 -

#include <iostream>
#include <string>
#include <thread>
#include <chrono>
#include <cmath>

using namespace std;

void show_progress_bar(int time, const std::string &message, char symbol)
{
    std::string progress_bar;
    const double progress_level = 1.42;

    std::cout << message << "\n\n";

    for (double percentage = 0; percentage <= 100; percentage += progress_level)
    {
        progress_bar.insert(0, 1, symbol);
        std::cout << "\r [" << std::ceil(percentage) << '%' << "] " << progress_bar;
        std::this_thread::sleep_for(std::chrono::milliseconds(time));       
    }
    std::cout << "\n\n";
}

int main()
{
    show_progress_bar(100, "progress" , '#');
}
于 2021-08-01T17:36:31.767 回答