#include <graphics.h> void pieslice(int x, int y, int stangle, int endangle, int radius);
The angles for pieslice are given in degrees. They are measured counterclockwise, with 0 degrees at 3 o'clock, 90 degrees at 12 o'clock, and so on.
If you're using a CGA or monochrome adapter, the examples in online Help that show how to use graphics functions might not produce the expected results. If your system runs on a CGA or monochrome adapter, use the value 1 (one) instead of the symbolic color constant, and see the second example under arc whis shows how to use the pieslice function.
/* pieslice example */ 
#include <graphics.h>
#include <stdlib.h>
#include <stdio.h>
#include <conio.h>
int main(void)
{
   /* request autodetection */
   int gdriver = DETECT, gmode, errorcode;
   int midx, midy;
   int stangle = 45, endangle = 135, radius = 100;
   /* initialize graphics and local variables */
   initgraph(&gdriver, &gmode, "");
   /* read result of initialization */
   errorcode = graphresult();
   if (errorcode != grOk)    /* an error occurred */
   {
      printf("Graphics error: %s\n", grapherrormsg(errorcode));
      printf("Press any key to halt:");
      getch();
      exit(1);               /* terminate with an error code */
   }
   midx = getmaxx() / 2;
   midy = getmaxy() / 2;
   /* set fill style and draw a pie slice */
   setfillstyle(EMPTY_FILL, getmaxcolor());
   pieslice(midx, midy, stangle, endangle, radius);
   /* clean up */
   getch();
   closegraph();
   return 0;
}