#include <stdio.h>
#include <conio.h>
#include <graphics.h>
#include <math.h>
void main()
{
 int gd=DETECT;
 int gm=DETECT;
 int dx,dy,Xa,Ya,Xb,Yb,c,r,p,f;
 detectgraph(&gm, &gd);
 initgraph(&gm,&gd,"c:\\tc\\bgi");
 cleardevice();
 printf("\n\n\n\n\t\t\tEnter your first X-coordinates: ");
 scanf("%d",&Xa);
 printf("\t\t\tEnter your first Y-coordinates: ");
 scanf("%d",&Ya);
 printf("\t\t\tEnter your second X-coordinates: ");
 scanf("%d",&Xb);
 printf("\t\t\tEnter your second Y-coordinates: ");
 scanf("%d",&Yb);
 printf("\n\n\n\n\n\t\t\t\t      WAIT!");
 dx=fabs(Xb-Xa);
 dy=fabs(Yb-Ya);
 p=dy-2*(dx);
 if(Ya > Yb)
 {
   c=Xb;
   r=Yb;
   f=Ya;
 }
 else
 {
  c=Xa;
  r=Ya;
  f=Yb;
 }
 do
 {
   if(p<0)
   {
    c=c-1;
    r=r+1;
    p=p-2*(fabs(dx)-fabs(dy));
    }
   else
   {
     r=r+1;
     p=(p-2*fabs(dx));
   }
   putpixel(c,r,YELLOW);
 }
 while(r<=f);
 getch();
 line(Xa,Ya,Xb,Yb);
 getch();
 closegraph();
 }

 /*blackout()
 {
  int i,j;
  for(i=0;i<640;i++)
  {
   for(j=0;j<480;j++)
    putpixel(j,i,BLACK);
  }
 } */