The ellipse is also a symmetric figure like a circle but is four-way symmetry rather than eight-way.

Program to Implement Ellipse Drawing Algorithm:

1. #include<stdio.h>  
2. #include<conio.h>  
3. #include<graphics.h>  
4. #include<math.h>  
5. void disp();  
6. float x,y;  
7. intxc,yc;  
8. void main()  
9. {  
10.                 intgd=DETECT,gm,a,b;  
11.                 float p1,p2;  
12.                 clrscr();  
13.                 initgraph(&gd,&gm,"c:\\turboc3\\bgi");  
14.                 printf("*** Ellipse Generating Algorithm ***\n");  
15.                 printf("Enter the value of Xc\t");  
16.                 scanf("%d",&xc);  
17.                 printf("Enter the value of yc\t");  
18.                 scanf("%d",&yc);  
19.                 printf("Enter X axis length\t");  
20.                 scanf("%d",&a);  
21.                 printf("Enter Y axis length\t");  
22.                 scanf("%d",&b);  
23.                 x=0;y=b;  
24.                 disp();  
25.                 p1=(b*b)-(a*a*b)+(a*a)/4;  
26.                 while((2.0*b*b*x)<=(2.0*a*a*y))  
27.                 {  
28.                                 x++;  
29.                                 if(p1<=0)  
30.                                 p1=p1+(2.0*b*b*x)+(b*b);  
31.                                 else  
32.         {  
33.                                                 y--;  
34.                                                 p1=p1+(2.0*b*b*x)+(b*b)-(2.0*a*a*y);  
35.          }  
36.                                disp();  
37.                                x=-x;  
38.                                disp();  
39.                                x=-x;  
40.                                delay(50);  
41.                  }  
42.                  x=a;  
43.                  y=0;  
44.                  disp();  
45.                  p2=(a*a)+2.0*(b*b*a)+(b*b)/4;  
46.                  while((2.0*b*b*x)>(2.0*a*a*y))  
47.                 {  
48.                                 y++;  
49.                                 if(p2>0)  
50.                                 p2=p2+(a*a)-(2.0*a*a*y);  
51.                                 else  
52.         {  
53.                                                 x--;  
54.                                                 p2=p2+(2.0*b*b*x)-(2.0*a*a*y)+(a*a);  
55.          }  
56.                                 disp();  
57.                                 y=-y;  
58.                                 disp();  
59.                                 y=-y;  
60.                                 delay(50);     
61.             }  
62.                 getch();  
63.                 closegraph();  
64. }  
65.  void disp()  
66. {  
67.               putpixel(xc+x,yc+y,7);  
68.                putpixel(xc-x,yc+y,7);  
69.                putpixel(xc+x,yc-y,7);  
70.           putpixel(xc+x,yc-y,7);  
71.   }  

Output:

There two methods of defining an Ellipse:

Exception Handling in Java - Javatpoint

1. Polynomial Method of defining an Ellipse
2. Trigonometric method of defining an Ellipse