DDA line drawing program in C++

source code:

/* Line drawing programme in c++ using DDA algorithm*/

#include<conio.h>

#include<iostream.h>

#include<dos.h>

#include<math.h>

#include<graphics.h>

void main()

{  float x,y,x1,y1,x2,y2,dx,dy,length;

   int i,gd=DETECT,gm;

   // Read two end point

   cout<<"Enter first point";

   cin>>x1>>y1;

   cout<<"Enter another point ";

   cin>>x2>>y2;

 // initializing the graphics mode

   initgraph(&gd,&gm,"c://TURBOC3//bgi");

   dx=abs(x2-x1);

   dy=abs(y2-y1);

   if(dx>=dy)

   {

   length=dx;

   }

   else {

   length=dy;

   }

    dx=(x2-x1)/length;

    dy=(y2-y1)/length;

    x=x1+0.5; //factor 0.5 is added to round the value

    y=y1+0.5;// factor 0.5 is added to round the value

    i=1;  // initialize the loop counter

    while(i<=length)

    {  putpixel(x,y,WHITE);

    x=x+dx;

    y=y+dy;

    i=i+1;

    delay(50); // to see every iteration or steps

    }

getch();

}

output: