Ellipse

#include<graphics.h> 
#include<conio.h> 
#include<stdio.h> 

void plotpoints(int cx,int cy, int x,int y) 
{ 
    putpixel(cx + x, cy + y,4); 
    putpixel(cx - x, cy + y,4); 
    putpixel(cx + x, cy - y,4); 
    putpixel(cx - x, cy - y,4); 
} 

void main() 
{ 
    int cx,cy,rx,ry; 

    printf("Enter the center "); 
    scanf("%d%d",&cx,&cy); 
    printf("x radius : "); 
    scanf("%d",&rx); 
    printf("y radius : "); 
    scanf("%d",&ry); 

    long rx2 = (long)rx*rx;
    long ry2 = (long)ry*ry;
    long trx2 = 2*rx2; 
    long try2 = 2*ry2; 
    long p,x=0, y=ry; 
    long px=0; 
    long py = trx2 * y; 

    p = (long) ( ( ry2 - (rx2 * ry) + (0.25 * rx2) ) + 0.5 ); 

    int gd=DETECT,gm=DETECT; 
    initgraph(&gd,&gm,""); 
    cleardevice(); 

    putpixel(cx,cy,15); 

    while(px<py) 
    { 
        plotpoints(cx,cy,x,y); 
        x++; 
        px += try2; 
        if(p < 0) 
            p += ry2 + px; 
        else 
        { 
            y--; 
            py -= trx2; 
            p += ry2 + px -py; 
        } 
    } 
    py=trx2*y; 
    px=try2*x; 
    p = (long) ( (ry2*(x+0.5)*(x+0.5) + rx2*(y-1)*(y-1) - rx2*ry2) + 0.5 ); 
    while(y>=0) 
    { 
        plotpoints(cx,cy,x,y); 
        y--; 
        py -= trx2; 
        if(p > 0) 
            p += rx2 - py; 
        else 
        { 
            x++; 
            px += try2; 
            p += rx2 - py + px; 
        } 
    } 

    getch(); 
}