#include <graphics.h>
void linerel(int dx, int dy);
 

linerel draws a line from the CP (current position) to a point that is a
relative distance (dx,dy) from the CP. The CP is advanced by (dx,dy).

/* linerel example */
 
#include <graphics.h>
#include <stdlib.h>
#include <stdio.h>
#include <conio.h>
 
int main(void)
{
   /* request autodetection */
   int gdriver = DETECT, gmode, errorcode;
   char msg[80];
 
   /* initialize graphics and local variables */
   initgraph(&gdriver, &gmode, "");
 
   /* read result of initialization */
   errorcode = graphresult();
   if (errorcode != grOk) {
printf("Graphics error: %s\n", grapherrormsg(errorcode));
printf("Press any key to halt:");
 
getch();
exit(1);
   }
 
   /* move the CP to location (20,30) */
   moveto(20,30);
 
   /* create and output a message at (20,30) */
   sprintf(msg, " (%d, %d)", getx(), gety());
   outtextxy(20,30, msg);
 
   /* draw line to a point a relative distance away from current CP */
   linerel(100, 100);
 
   /* create and output a message at CP */
   sprintf(msg, " (%d, %d)", getx(), gety());
   outtext(msg);
 
   /* clean up */
   getch();
   closegraph();
 
   return 0;
}

getlinesettings line lineto setcolor setlinestyle setwritemode

  no output of example at the moment
  do not hesitate and add it...