《数据结构》严蔚敏版（java解）——第三章 栈和队列02 链式栈操作

package csdn.wj.linear;

import csdn.wj.assistant.Node;
import csdn.wj.assistant.Stack;

public class Stack02 implements Stack {
private Node top;
private int size;
//链表首结点引用
//栈的大小
public Stack02() {
top = null;
size = 0;
}
//返回堆栈的大小
public int getSize() {
return size;
}
//判断堆栈是否为空
public boolean isEmpty() {
return size==0;
}
//数据元素 e入栈
public void push(Object e) {
Node tmp = top;
Node q = new Node((int)e);
q.next = tmp;
top = q;
size++;
}
//栈顶元素出栈
public Object pop() throws StackEmptyException {
if (size<1)
throw new StackEmptyException("错误，堆栈为空。");
int obj = top.data;
top = top.next;
size--;
return obj;
}
//取栈顶元素
public Object peek() throws StackEmptyException {
if (size<1)
throw new StackEmptyException("错误，堆栈为空。");
return top.data;
}
}