public class Connect4Column
{
    private int counters[];
    private int numCounters;
    private int MAX_NUM_COUNTERS;

    static int YELLOW_COUNTER = 1;
    static int RED_COUNTER = 2;

    public Connect4Column(int max_counters)
    {
        MAX_NUM_COUNTERS = max_counters;
        counters = new int[MAX_NUM_COUNTERS];
        numCounters = 0;
    }

    public boolean addCounter(int thisCounter)
    {
        if ((numCounters < MAX_NUM_COUNTERS)&&((thisCounter == 1)||(thisCounter == 2)))
        {
            counters[numCounters] = thisCounter;
            numCounters++;
            return true;
        }
        else
        {
            return false;
        }
    }

    public int getNumCounters()
    {
        return numCounters;
    }

    public int getCounter(int thisRow)
    {
        if ((thisRow >= 0)&&(thisRow <= numCounters))
        {
            return counters[thisRow];
        }
        else
        {
            return 0;
        }
    }
}