#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:\\turboc\\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);
 drawline(Xa,Ya,Xb,Yb);
 getch();
 line(Xa,Ya,Xb,Yb);
 getch();
}
drawline(int Xa,int Ya,int Xb,int Yb)
{
  int dx,dy,leng,xincr,i,x,y;
  float yincr;
  dx=Xb-Xa;
  dy=Yb-Ya;
  if(dx>dy)
  {
   leng=fabs(dx);
  }
  else
   leng=fabs(dy);
  xincr=dx/leng;
  x=Xb;
  yincr=dy/leng;
  y=Yb;
  for(i=0;i<leng;i++)
  {
   x+=xincr;
   y+=yincr;
   putpixel(x,y,RED);
  }
  return;
 }