#include <stdio.h>
#include <conio.h>
#include <graphics.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);
 blank();
 printf("\n\n\n\n\n\n\n\t\t\t\t\tWAIT!");
 blank();
 dx=Xb-Xa;
 dy=Yb-Ya;
 p=dy-2*dx;
 if((Xb-Xa)>(Yb-Ya))
 {
 if(Xa>Xb)
 {
   c=Xb;
   r=Yb;
   f=Xa;
 }
 else
 {
  c=Xa;
  r=Ya;
  f=Xb;
 }
 putpixel(c,r,YELLOW);
 do
 {
   c=c+1;
   if(p<0)
    p=p+2*dy;
   else
   {
    r=r+1;
    p=p+2*(dy-dx);
   }
   putpixel(c,r,YELLOW);
 }while(c<f);
 }
  else
 {
 if(Xa>Xb)
 {
   c=Xb;
   r=Yb;
   f=Xa;
 }
 else
 {
  c=Xa;
  r=Ya;
  f=Xb;
 }
 putpixel(c,r,YELLOW);
 do
 {
   c=c+1;
   if(p<0)
    p=p+2*dy;
   else
   {
    r=r+1;
    p=p+2*(dy-dx);
   }
   putpixel(c,r,YELLOW);
 }while(c<f);
 }
 getch();
 blank();
 line(Xa,Ya,Xb,Yb);
 getch();
 blank();
}
blank()
{
 int i,j;
 for(i=0;i<648;i++)
 {
  for(j=0;j<680;j++)
    putpixel(j,i,BLACK);
 }
}