Bresenham Dot Algorithm

#include<stdio.h>
#include<conio.h>
#include<graphics.h>
#include<dos.h>
#include<math.h>

void main(){
 int i,x1,x2,y1,y2,p,steps,xinc,yinc,dx,dy;
 int gd=DETECT,gm;
 initgraph(&gd,&gm,"C:\\TURBOC3\\BGI");

 printf("Enter first x and y coor\n");
 scanf("%d%d",&x1,&y1);
 printf("Enter second x and y coor\n");
 scanf("%d%d",&x2,&y2);
 dx=x2-x1;
 dy=y2-y1;
 p=2*dy-dx;
 while(x1<=x2){
  putpixel(x1,y1,3);
  x1++;
  if(x1%2==0){
  if(p<0){
   p=p+2*dy;
  }
  else{
   p=p+2*dy-2*dx;
   y1++;
   delay(60);
   }
  }
 }
 getch();
 closegraph();
}