Command Line Progress Bar (C/C++ and/or Java)

Command Line Progress Bar (C/C++ and/or Java)

bamccaig

Member #7,536

July 2006

I am looking for an explanation/instructions on how some command-line applications show progress bars. For example,

prompt>./dosomething

	Doing something... Progress: [===========         ] 55%

Does anybody know how this is done? I am looking for a solution that doesn't require clearing the screen with 'clear' or 'cls', etc. For example, the Linux update utility 'yum' shows similar progress bars on the command-line. You can still scroll up through previous output so clearly it is possible, at least in some cases, to achieve this without any crazy clearing of screens.

I'm quite confident that it is possible with C/C++ in at least Windows and Linux (which I assume implies most Unix-like systems as well), although I don't know how or which libraries would achieve this.

My instincts tell me it would be shell and operating system dependent, but I don't want excuses. I want results!

As implied in the title of this thread, I am also interested in doing this with Java. Does anybody know of packages that can achieve this on the command-line?

Your comments are appreciated.

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I mean the best with what I say. It doesn't always sound that way.

Steve Terry

Member #1,989

March 2002

I think you can use a special escape character, like /r to move the cursor to the beginning of the line.

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Matthew Dalrymple

Member #7,922

October 2006

If you want complete control of the console window (changing colors, mouse support, cursor control)
Check out this and the related functions:
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dllproc/base/writeconsole.asp
SetConsoleCursorPosition()
etc...

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Steve Terry

Member #1,989

March 2002

1#include <stdio.h>
2#include <stdlib.h>
3#include <windows.h>
4#include <winbase.h>
5 
6int main(int argc, char **argv)
7{
8  char buffer[256] = { 0 };
9  char percent[7] = "0.0%%";
10  int i, j, k;
11  buffer[0] = '[';
12  for(i = 0; i < 40; i++)
13  {
14    buffer[i + 1] = '=';
15    j = i % 4;  
16    if(j == 0)
17      buffer[i + 2] = '\\';
18    else if(j == 1)
19      buffer[i + 2] = '|';
20    else if(j == 2)
21      buffer[i + 2] = '/';
22    else
23      buffer[i + 2] = '-';
24    
25    for(k = i + 3; k < 41; k++)
26      buffer[k] = ' ';
27 
28    buffer[41] = ']';
29 
30    sprintf(percent, "%3.2f%%", (i / 40.0) * 100.0);
31 
32    printf("%s%s\r", buffer, percent);
33    
34    Sleep(200);
35  }
36 
37  sprintf(percent, "%3.2f%%", (i / 40.0) * 100.0);
38 
39  printf("%s%s\r", buffer, percent);
40 
41  return 0;
42}

I was bored

bamccaig

Member #7,536

July 2006

Thank you both! The \r is working and I also discovered that generating the string before printing it speeds up the line and makes the caret appear only at the end of the line flashing, as opposed to flashing inside of the progress bar ugly-ly.

I also appreciate the article about controlling the command line. I will definitely look at that!

Thanks again! 8-)

--
I mean the best with what I say. It doesn't always sound that way.

Goalie Ca

Member #2,579

July 2002

If you want more control over it i suggest looking into ncurses.

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