Bresen Line Drawing Program IN C( GRAPHICS)

#include<stdio.h>

#include<conio.h>

#include<graphics.h>

void main()

{

      int gd = DETECT, gm;

      int dx, dy, p, end;

      float x1, x2, y1, y2, x, y;

      initgraph(&gd, &gm, "c:\tc\bgi");

      printf("Enter Value of X1: ");

      scanf("%f", &x1);

      printf("Enter Value of Y1: ");

      scanf("%f", &y1);

      printf("Enter Value of X2: ");

      scanf("%f", &x2);

      printf("Enter Value of Y2: ");

      scanf("%f", &y2);

      dx = abs(x1 - x2);

      dy = abs(y1 - y2);

      p = 2 * dy - dx;

      if(x1 > x2)

      {

            x = x2;

            y = y2;

            end = x1;

      }

      else

      {

            x = x1;

            y = y1;

            end = x2;

      }

      putpixel(x, y, 10);

      while(x < end)

      {

            x = x + 1;

            if(p < 0)

            {

                  p = p + 2 * dy;

            }

            else

            {

                  y = y + 1;

                  p = p + 2 * (dy - dx);

            }

            putpixel(x, y, 10);

      }

      getch();

      closegraph();

}