Bbresenham Midpoint Ellipse Algotithm

# include<stdio.h> 
# include<conio.h> 
# include<math.h> 
# include <graphics.h> 
int xcentre, ycentre, rx, ry; 
int p,px,py,x,y,rx2,ry2,tworx2,twory2; 
void drawelipse(); 
void main() 
{
int gd=3,gm=1; 
clscr(); 
initgraph(&gd,&gm,””); 
printf(“n Enter X center value: “); 
scanf(“%d”,&xcentre); 
printf(“n Enter Y center value: “); 
scanf(“%d”,&ycentre); 
printf(“n Enter X redius value: “); 
scanf(“%d”,&rx); 
printf(“n Enter Y redius value: “); 
scanf(“%d”,&ry); 
cleardevice(); 
ry2=ry*ry; 
rx2=rx*rx; 
twory2=2*ry2; 
tworx2=2*rx2; 
/* REGION first */ 
x=0; 
y=ry; 
drawelipse(); 
p=(ry2-rx2*ry+(0.25*rx2)); 
px=0; 
py=tworx2*y; 
while(px<py) 
{ 
x++; 
px=px+twory2; 
if(p>=0) 
{ 
 
 y=y-1; 
 py=py-tworx2; 
 } 
 if(p<0) 
 p=p+ry2+px; 
 else 
 { 
 p=p+ry2+px-py; 
drawelipse(); 
 } 
} 
/*REGION second*/ 
 p=(ry2*(x+0.5)*(x+0.5)+rx2*(y-1)*(y-1)-rx2*ry2);
 while(y>0) 
 { 
 y=y-1: 
 py=py-tworx2; 
 if(p<=0) 
 { 
 x++; 
 px =px + twory2; 
} 
if(p >0) 
 p=p+rx2-py; 
else 
{ 
 p=p+rx2-py+px; 
 drawelipse(); 
 } 
} 
 getch(); 
 closegraph(); 
} 
void drawelipse() 
{ 
Putpixel (xcenter +x, ycenter +y, BROWN); 
putpixel (xcenter +x, ycenter +y, BROWN); 
putpixel (xcenter +x, ycenter +y, BROWN); 
putpixel (xcenter +x, ycenter +y, BROWN); 
}