Lab 4 Midpoint Ellipse Algorithm.CPP

#include <stdio.h>
#include <conio.h>
#include <graphics.h>
void main()
{
    int gd = DETECT, gm = DETECT;
    float p, x, y, xc, yc, a, b; // a, b bhaneko semi major ra semi minor axis
    initgraph(&gd, &gm, "C:\\TURBOC3\\BGI");
    cleardevice();
    printf("Enter xc, yc:\n");
    scanf("%f%f", &xc, &yc);
    printf("Enter a, b:\n");
    scanf("%f%f", &a, &b);
    x = 0;
    y = b;
    // Region 1 ko lagi
    p = (b * b) - (a * a * b) + (0.25 * a * a);
    do
    {
        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 * b * b * x + b * b;
        }
        else
        {
            x = x + 1;
            y = y - 1;
            p = p + 2 * b * b * x - 2 * a * a * y + b * b;
        }
    } while (2 * b * b * x < 2 * a * a * y);
    // Region 2 ko lagi
    p = (b * b * (x + 0.5) * (x + 0.5)) + ((y - 1) * (y - 1) * a * a - a * a * b * b);
    do
    {
        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 * a * a * y + a * a;
        }
        else
        {
            x = x + 1;
            y = y - 1;
            p = p - 2 * a * a * y + 2 * b * b * x + a * a;
        }
    } while (y != 0);
    getch();
    closegraph();
}