#define MAX_ELEMENT_VALUE 255 // maximum value that an element 
                              // can have (e.g., 255 or 4096)
#define BIN_WIDTH 1           // values spanned by each bin
#define X 1920 // total number of X pixels
#define X 1080 // total number of Y pixels


struct pixel {
  unsigned int r, g, b;
}; 

// compute the R,G, and B histograms for an image
// parameters defined as pre-processor constants above
void histogram(pixel** image, unsigned int* r_hist, 
               unsigned int* g_hist, unsigned int* b_hist) {
  for (int x=0; x<X; x++) {
    for (int y=0; y<Y; y++) {
      unsigned int r_bin = image[x][y].r / BIN_WIDTH;
      r_hist[r_bin]++;       
      unsigned int g_bin = image[x][y].g / BIN_WIDTH;
      g_hist[g_bin]++;       
      unsigned int b_bin = image[x][y].b / BIN_WIDTH;
      b_hist[b_bin]++;       
    }
  }
}