MystackList

class Node<E>{
    Node<E>next=null;
    E data;
    public Node(E data){
        this.data = data;
    }
}    
    
public class MystackList<E>{
    Node<E>top=null;
    public boolean Empty(){
        return top==null;
    }
    public void push(E data){
        Node<E>newNode=new Node<E>(data);
        newNode.next = top;
        top = newNode;
    }
    public E pop(){
        if(this.Empty()){
            return null;
        }
        E data = top.data;
        top = top.next;
        return data;
    }
    public E peek(){
        if(this.Empty()){
            return null;
        }
        return top.data;
    }
    
    public static void main(String[] args){
        MystackList<Integer>s=new MystackList<Integer>();
        s.push(1);
        s.push(2);
        System.out.println("栈顶元素为："+s.pop());
        System.out.println("栈顶元素为："+s.pop());
    }
}