public int check_end_of_game() { //Returns 0 if fail, 1 if game over red wins, 2 if game over black wins
		int black_num = 0;
		int red_num = 0;
		
		for(int i = 0; i<columns; i++) {
			for(int j = 0; j<rows; j++) {				
				if(game_board_array[i][j] == RED) red_num++;
				if(game_board_array[i][j] == BLACK) black_num++;
			}
		}
		
		if(black_num == 0) return 1;
		else if(red_num == 0) return 2;
		else return 0;
	}