Q34923: Corrections to the _setbkcolor Example

Article: Q34923
Product(s): See article
Version(s): 5.00 5.10 | 5.10
Operating System(s): MS-DOS | OS/2
Keyword(s): ENDUSER | docerr | mspl13_c
Last Modified: 12-OCT-1988

Problem:

The example program on Page 515 of the "Microsoft C 5.0 (and 5.1)
Optimizing Compiler Run-Time Library Reference" and the "Microsoft
QuickC Run-Time Library Reference" is supposed to run through 20
different background colors, displaying the use of _setbkcolor. When I
try to run the program, my screen flickers and I am returned to the
DOS prompt.

Response:

The example is incorrect. The following example changes the background
color in graphics mode (this example can be found on the Libraries 1
disk of the QuickC Version 1.01 compiler, in PROGRAMS\SBKCOL.C):

#include <stdio.h>
#include <graph.h>

long color[16] = {_BLACK,_BLUE,_GREEN,_CYAN,_RED,_MAGENTA,
     _BROWN,_WHITE,_GRAY,_LIGHTBLUE,_LIGHTGREEN,_LIGHTCYAN,
     _LIGHTRED,_LIGHTMAGENTA,_LIGHTYELLOW,_BRIGHTWHITE};

main()
{
 int loop;
 long i;
 _setvideomode(_HRES16COLOR);
 for (loop = 0; loop < 16; loop++ ) {
 _setbkcolor(color[loop]);
 for (i=0; i < 50000; i++)     /* null loop */
    ;
 _setvideomode (_DEFAULTMODE);
}

The next example changes the background color in text mode:

#include <stdio.h>
#include <graph.h>

main()
{
  long loop;
  for (loop = 0; loop < 16; loop++)
    {
      _setbkcolor(loop);
      _outtext("    hello    \n");
    }
}

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