Mandelbrot set

mandelbrot.cpp

// from http://blog.nothinguntoward.eu/?p=38

#include <cstdio>
#include <cmath>

using namespace std;

int main() {

  const int width  = 80;
  const int height = 80;
  const int zoom   = 20;

  for (int i = 0; i < width; i++) {
    for (int j = 0; j < height; j++) {

      // scale the indicies to floats in the range -2..2
      const float cr = float(j - (width  / 2)) / float(zoom);
      const float ci = float(i - (height / 2)) / float(zoom);

      // initialise z to 0
      float zr = 0;
      float zi = 0;

      for (int iter = 0; iter < 64; iter++) {
        const float tr = zr * zr - zi * zi + cr;
        const float ti = zr * zi + zi * zr + ci;
        zr = tr;
        zi = ti;
      }

      const float m = 2.f;
      const float v = zr * zr + zi * zi;

      printf("%s", (v < m*m) ? "1" : "0");
    }
    printf("\n");
  }
  return 0;
}