#include <stdio.h>

double xmin = -2;
double xmax = 1;
int xstep = 256;
double ymin = -1;
double ymax = 1;
int ystep = 256;
int iters = 100000;

int escapes(double cr, double ci, int it) { 
  double zr = 0;
  double zi = 0;
  double zrtmp;
  int i;
  
  for(i=0; i<it; i++) {
    // z <- z^2 + c
    zrtmp = zr*zr - zi*zi + cr;
    zi = 2*zr*zi + ci;
    zr = zrtmp;
    if (zr*zr + zi*zi > 4) {
      return 1;
    }
  }
  return 0;
}

// ----------------------------------------------
// main function
// ----------------------------------------------
int main() {
  int xc, yc;
  double x, y;
  
  // array of string to store result
  char m[256][257];
  
  #pragma omp parallel for private (xc, x, y)
  for(yc=0; yc<ystep; yc++) {
    y = yc*(ymax-ymin)/ystep + ymin;
    for(xc=0; xc<xstep; xc++) {
      x = xc*(xmax-xmin)/xstep + xmin;
      escapes(x, y, iters);
      if (escapes(x, y, iters)) {
        m[yc][xc] = ' ';
      } else {
        m[yc][xc] = 'X';   
      }
    }
    // add end of string
    m[yc][xc] = '\0';  
    
  }
  
  #pragma omp barrier
  for(yc=0; yc<ystep; yc++) {
	  printf("%s\n", m[yc]);
  }
  return 0;
}