C/C++ Program to draw circle using second order mid point approach

//Program to draw circle using second order mid point approach

Source code

#include<dos.h>

#include <graphics.h>

#include <stdlib.h>

#include <stdio.h>

#include <conio.h>

void plotcircle(int x,int y,int a,int b)

{

int xmax=getmaxx();

int ymax=getmaxy();

putpixel(x+xmax/2+a,ymax/2-y-b,15);

putpixel(xmax/2+y+a,ymax/2-x-b,15);

putpixel(x+xmax/2+a,ymax/2+y-b,15);

putpixel(y+xmax/2+a,ymax/2+x-b,15);

putpixel(xmax/2-x+a,ymax/2-y-b,15);

putpixel(xmax/2-y+a,ymax/2-x-b,15);

putpixel(xmax/2-x+a,ymax/2+y-b,15);

putpixel(xmax/2-y+a,ymax/2+x-b,15);

}

int main(void)

{

  /* request auto detection */

  int gdriver = DETECT, gmode, errorcode;

  int xmax, ymax,x,y,i,de=3,dse;

  int r,a,b,d;

  printf("Enter the value radius and center ");

  scanf("%d%d%d",&r,&a,&b);

  dse=5-2*r;

  clrscr();

  /* initialize graphics and local variables */

  initgraph(&gdriver, &gmode, "");

  /* read result of initialization */

  errorcode = graphresult();

  /* an error occurred */

  if (errorcode != grOk)

  {

     printf("Graphics error: %s\n", grapherrormsg(errorcode));

     printf("Press any key to halt:");

     getch();

     exit(1);

  }

  setcolor(getmaxcolor());

  xmax = getmaxx();

  ymax = getmaxy();

  x=xmax/2;

  y=ymax/2;

  d=1-r;

  for(i=0;i<xmax;i++)

   putpixel(i,y,15);

  for(i=0;i<ymax;i++)

   putpixel(x,i,15);

  x=0;

  y=r;

  while(y>=x)

   {

    if(d<0)

     {

      d+=de;

      de+=2;

      dse+=2;

      x++;

     }

    else

     {

      d+=dse;

      de+=2;

      dse+=4;

      x++;

      y--;

     }

    plotcircle(x,y,a,b);

    delay(100);

   }

  /* clean up */

  getch();

  closegraph();

  return 0;

}