In line 104 `if ( full_neg_lst[i].cols >= box.width && full_neg_lst[i].rows >= box.height )` removed '=' as it causes divide By Zero Error in line 106 and 107 `box.x = rand() % ( full_neg_lst[i].cols - size_x );` when  full_neg_lst[i].cols = size_x or full_neg_lst[i].rows - size_y