顺序栈的实现

package Stack;
/**
 * 顺序栈的实现
 * @author baby69yy2000
 */
public class ALStack<T> {
	
	private int maxSize;
	private T[] stackArray;
	private int top;
	
	public ALStack(int s) {
		maxSize = s;
		stackArray = (T[])new Object[maxSize];
		top = -1;
	}
	
	//测试堆栈是否为空
	public boolean isEmpty() {
		return top == -1;
	}
	
	//测试堆栈是否满了
	public boolean isFull() {
		return top == maxSize - 1;
	}
	
	//把项压入堆栈顶部
	public void push(T item) {
		if(isFull()) {
			System.err.println("Stack overflow!");
			System.exit(1);
		}
		top++;
		stackArray[top] = item;
	}
	
	//移除堆栈顶部的对象，并作为此函数的值返回该对象
	public T pop() {
		T tmp;
		if(isEmpty()) {
			System.err.println("Attempt to pop an empty stack!");
			System.exit(1);
		}
		tmp = stackArray[top];
		top--;
		return tmp;
	}
	
	//查看堆栈顶部的对象，但不从堆栈中移除它
	public T peek() {
		if(isEmpty()) {
			System.err.println("Attempt to pop an empty stack!");
			System.exit(1);
		}
		return stackArray[top];
	}
	

	public static void main(String[] args) {
		ALStack<Integer> s = new ALStack<Integer>(10);
		s.push(new Integer(10));
		s.push(new Integer(20));
		s.push(new Integer(30));
		while(!s.isEmpty()) {
			System.out.println(s.pop()); //30 20 10
		}
	}

}