DDA Dash Algorithm

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

void main(){
 int i,x1,x2,y1,y2,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;
 if(abs(dx)>abs(dy)){
  steps=abs(dx);
 }
 else{
  steps=abs(dy);
 }
 xinc=dx/steps;
 yinc=dy/steps;

 for(i=0;i<steps;i++){
  if(i%4!=0){
  putpixel(x1,y1,3);
  }
  x1=x1+xinc;
  y1=y1+yinc;
 }
 getch();
 closegraph();
}