#include<bits/stdc++.h>
using namespace std;
struct Node
{
    int val;
    Node* next;
    Node(int x):val(x),next(NULL){};
};
Node* init()
{
    Node* dummy=new Node(-1);
    return dummy;
}
bool empty(Node* dummy)
{
    return dummy->next==NULL;
}
void push(Node* dummy,int x)
{
    Node* node=new Node(x);
    node->next=dummy->next;
    dummy->next=node;
}
void pop(Node* dummy)
{
    dummy->next=dummy->next->next;
}
int top(Node* dummy)
{
    return dummy->next->val;
}
void print(Node* dummy)
{
    while(!empty(dummy))
    {
        cout<<top(dummy)<<' ';
        pop(dummy);
    }
}
int main()  
{
    Node *dummy = init();
    push(dummy, 1);
    push(dummy, 2);
    push(dummy, 3);
    push(dummy, 4);

    printf("栈顶元素：%d\n", top(dummy));

    pop(dummy);

    printf("栈顶元素：%d\n", top(dummy));

    printf("栈是否为空：%d\n", empty(dummy));

    print(dummy);

    return 0;
}