Plot the implicit curve 9x2 + 4y2 = 3600

elipseImplicita.cpp

// elipseImplicita.cpp
// juanfc 2016-11-04
// Plot the implicit curve:
//    9x2 + 4y2 = 3600
// It approximates as part of the curve, dots in the
// range of ALLOWANCE
// https://gist.github.com/fb15ff4fead7621813aa99c2f76c0152


#include <iostream>
#include <cmath>
using namespace std;

const int HEIGHT  = 31; // ~ sqrt(3600/9)
const int WIDTH   = 31; // ~ sqrt(3600/4)
const float ALLOWANCE = 110;

int main()
{
    for (int lin = -HEIGHT; lin < HEIGHT; ++lin) {
        for (int col = -WIDTH; col < WIDTH; ++col)
            if (fabs(4*lin*lin + 9*col*col - 3600) < ALLOWANCE)
                cout << '*';
            else
                cout << ' ';
        cout << endl;
    }

    return 0;
}