/**
 * Write a description of class StackGen here.
 *
 * @author (your name)
 * @version (a version number or a date)
 */
public class StackGen<T>
{
    int MAX = 30;
    private int top;
    private T[] stack;
    public StackGen()
    {
        top = MAX;
        stack = (T[]) new Object[MAX];
    }
    public void push(T dataItem)
    {
        assert(top>0);
        top = top-1;
        stack[top] = dataItem;
    }
    public T pop()
    {
        assert(top < MAX);
        T variable = stack[top];
        top = top + 1;
        return variable;
    }
    public int getSize()
    {
        return MAX-top;
    }
    public T getTop()
    {
        assert(top < MAX);
        return stack[top];
    }
}