#include <stdio.h>
#include <stdlib.h>
#include <malloc.h>
typedef int elemType;
typedef struct linklist
{
    elemType data;
    struct linklist *next;
} node, *linklist;
linklist initLinklist()
{
    linklist s;
    s = (linklist)malloc(sizeof(node));
    s->next = NULL;
    return
 
 s;
}
int PushLinkStack(linklist s, elemType e)
{
    linklist new;
    new = (linklist)malloc(sizeof(node));
    if (!new)
    {
        printf("node  is  null\n");
        return 0;
    }
    new->data = e;
    new->next = s->next;
    s->next = new;
    return 1;
}
void printStack(linklist s)
{
    linklist p 
 
= s->next;
    if (s->next == NULL)
    {
        printf("stack is null\n");
    }
    while (p)
    {
        printf("%d<-", p->data);
        p = p->next;
    }

    printf("\n");
}
void popLinkStack(linklist s)
{
    linklist p;
    p = s->next;
    if (s->next == NULL)
    {
        printf(
 
"當前棧為空\n");
        return;
    }
    else
    {
        s->next = p->next;
        free(p);
        p = NULL;
    }
}
elemType getLinkTop(linklist s)
{
    linklist p;
    if (s->next != NULL)
    {
        p = s->next;
        return p->data;
    }
    else
    {
        printf("stack is  null\n");
    }
}
void clearStack(linklist s)
{
    linklist p, q;
    p = s->next;
    while (p)
    {
        q = p;
        p = p->next;
        free(q);
        q = NULL;
    }
    s->next = NULL;
    s->data = 0;
}
int main()
{
    elemType e;
    linklist s;
    int topElem;
    s = initLinklist();
    s->data = 0; //表示棧當前長度
    if (s)
    {
        printf("初始化成功\n");
    }
    printf("十次入棧\n");
    for (int i = 0; i < 10; i++)
    {
        if (PushLinkStack(s, i + 1))
        {
            s->data++;
        }
    }
    printf("當前棧長度為：%d\n", s->data);
    printf("Linklist:\n");
    printStack(s);
    printf("取棧頂元素：%d\n", getLinkTop(s));
    printf("執行四次出棧操作：\n");
    for (int i = 0; i < 4; i++)
    {
        popLinkStack(s);
        s->data--;
    }
    printf("當前棧長度為：%d\n", s->data);
    printf("Linklist:\n");
    printStack(s);
    printf("取棧頂元素：%d\n", getLinkTop(s));
    printf("清空棧\n");
    clearStack(s);
    printStack(s);

    return 0;
}