DDA (Digital Differential Analyzer) line drawing algorithm in Graphics

#include <graphics.h>

#include <stdio.h>

#include <math.h>

float x,y,x1,y1,x2,y2,dx,dy,pixel;

int i;

void main( )

{

  int gd = DETECT,gm;

  initgraph(&gd,&gm,"c:\\tc\\bgi");

  printf("Enter the value of x1 : ");

  scanf("%f",&x1);

  printf("Enter the value of y1 : ");

  scanf("%f",&y1);

  printf("Enter the value of x2 : ");

  scanf("%f",&x2);

  printf("Enter the value of y2 : ");

  scanf("%f",&y2);

  

  dx=abs(x2-x1);

  dy=abs(y2-y1);

  if(dx>=dy)

    pixel=dx;

  else

    pixel=dy;

  

  dx=dx/pixel;

  dy=dy/pixel;

  x=x1;

  y=y1;

  

  i=1;

  while(i<=pixel)

  {

    putpixel(x,y,1);

    x=x+dx;

    y=y+dy;

    i=i+1;

    delay(100);

  }

  getch();

  closegraph();

}

OUTPUT:

Bresenham's Algorithm in Graphics >>