java实现栈（分别基于数组和基于链表）_此栈

package com.ma.stack;
 
/**
 * @author xiaoma
 *此栈实现基于数组，初始栈时已经设置栈大小
 */
public class MyArrayStack {
	private int size;
	private int top = -1;
	private int[] arr;
 
	MyArrayStack(){
		arr =new int[3]; //默认栈大小为3
	}
	MyArrayStack(int size) {
		if(size > 0){
			this.size = size;
			arr = new int[size];
		}
		else throw new RuntimeException("数组长度值不正确");
	}
	//==============================================================================
	//入栈
	public void push(int data){
		if(top >= size-1){
			System.out.println("栈已满");
			return;
		}
		arr[++top] = data;
	}
	//==============================================================================
	//出栈
	public int pop(){
		if(top < 0){
			throw new RuntimeException("栈为空");
		}
		else{
			int temp = arr[top];
			arr[top] = 0;
			top--;
			return temp;
		}
	}
	
	//查看栈顶元素但不出栈
	public int peek(){
		if(top < 0){
			throw new RuntimeException("栈为空");
		}
		else{
			return arr[top];
		}
	}
	//==============================================================================
	
	public boolean isEmpty(){
		return top == -1;
	}
 
	//==============================================================================
 
	public static void main(String[] args) {
		MyArrayStack stack = new MyArrayStack(3);//初始栈大小为3
		stack.push(2);
		stack.push(5);
		stack.push(10);
		//stack.push(11);
		System.out.println(stack.pop());
		System.out.println(stack.pop());
		System.out.println(stack.pop());
		//System.out.println(stack.pop());
//		System.out.println(stack.peek());
//		System.out.println(stack.peek());
		System.out.println(stack.isEmpty());
		
	}
 
}

基于链表如下：

package com.ma.stack;
 
/**
 * @author xiaoma
 * 此栈实现基于链表，初始栈时未设置栈大小（栈大小可变）
 *此栈是将新元素插到链表头部（链表头部是栈顶）
 */
public class MyLinkStack {
	private Node top;//记录栈顶元素
	private int size = 0;//记录栈大小
 
	
	public MyLinkStack() {
		top = null;
	}
	class Node{
		public int data; //记录数据
		public Node next;
		Node(int data){
			this.data = data;
		}
	}
	
//=============================================================================================	
	//入栈
	public void push(int data){
		Node newNode = new Node(data);
		if(top == null){
			top =newNode;
			
			
		}
		else{
			newNode.next = top;//将新元素插到链表头部
			top = newNode;
		}
		size++;
	}
//=============================================================================================	
	//出栈
	public Integer pop(){
		if(top == null) throw new RuntimeException("栈为空");
		else{
			int val = top.data;
			top = top.next;
			size--;
			return val;
		}
		
	}
	//查看栈顶元素但不出栈
	public Integer peek(){
		if(top == null) throw new RuntimeException("栈为空");
		else{
			return top.data;
		}
		
	}
//=============================================================================================	
	
	public boolean isEmpty(){
        return top == null;
    }
	
	public int getSize(){
		return size;
	}
	
//=============================================================================================	
 
	public static void main(String[] args) {
		MyLinkStack my = new MyLinkStack();
		my.push(4);
		my.push(5);
		my.push(6);
		System.out.println("当前size："+my.getSize());
		System.out.println(my.isEmpty());
		System.out.println(my.pop());
		System.out.println("当前size："+my.getSize());
		System.out.println(my.pop());
		System.out.println(my.pop());
		System.out.println(my.isEmpty());
		//System.out.println(my.pop());
	}
}