创建固定大小的堆栈

您可以创建一个非常简单的堆栈，如下所示：

public class FixedStack<T>{    private T[] stack;    private int size;    private int top;    public FixedStack<T>(int size)    {        this.stack = (T[]) new Object[size];        this.top = -1;        this.size = size;    }    public void push(T obj)    {        if (top >= size) throw new IndexOutOfBoundsException("Stack size = " + size);        stack[++top] = obj;    }    public T pop()    {        if (top < 0) throw new IndexOutOfBoundsException();        T obj = stack[top--];        stack[top + 1] = null;        return obj;    }    public int size()    {        return size;    }    public int elements()    {        return top + 1;    }}