C program to draw ellipse using Midpoint Ellipse Algorithm.

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#include<stdio.h> #include<conio.h> #include<graphics.h> void ellipse(int xc,int yc,int rx,int ry) { int gm=DETECT,gd; int x, y, p; clrscr(); initgraph(&gm,&gd,"C:\\TC\\BGI"); x=0; y=ry; p=(ry*ry)-(rx*rx*ry)+((rx*rx)/4); while((2*x*ry*ry)<(2*y*rx*rx)) { putpixel(xc+x,yc-y,WHITE); putpixel(xc-x,yc+y,WHITE); putpixel(xc+x,yc+y,WHITE); putpixel(xc-x,yc-y,WHITE); if(p<0) { x=x+1; p=p+(2*ry*ry*x)+(ry*ry); } else { x=x+1; y=y-1; p=p+(2*ry*ry*x+ry*ry)-(2*rx*rx*y); } } p=((float)x+0.5)*((float)x+0.5)*ry*ry+(y-1)*(y-1)*rx*rx-rx*rx*ry*ry; while(y>=0) { putpixel(xc+x,yc-y,WHITE); putpixel(xc-x,yc+y,WHITE); putpixel(xc+x,yc+y,WHITE); putpixel(xc-x,yc-y,WHITE); if(p>0) { y=y-1; p=p-(2*rx*rx*y)+(rx*rx); } else { y=y-1; x=x+1; p=p+(2*ry*ry*x)-(2*rx*rx*y)-(rx*rx); } } getch(); closegraph(); } void main() { int xc,yc,rx,ry; clrscr(); printf("Enter Xc="); scanf("%d",&xc); printf("Enter Yc="); scanf("%d",&yc); printf("Enter Rx="); scanf("%d",&rx); printf("Enter Ry="); scanf("%d",&ry); ellipse(xc,yc,rx,ry); getch(); }

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