实现链栈的插入和删除

#include <stdio.h>
#include <malloc.h>
#include <intrin.h>

typedef struct Node
{
    int data;
    struct Node *next;
}*lstack;
//创建
lstack create()
{
    lstack s=(lstack)malloc(sizeof (struct Node));
    if(s==NULL)
    {
        return NULL;
    }
    s->data=0;
    s->next=NULL;
    return s;
}
//插入（头插）
lstack insert(lstack L,int element)
{
    lstack s=create();
    if(L==NULL)
    {
        s->data=element;
        L=s;
    } else
    {
        s->next=L->next;
        s->data=L->data;
        L->next=s;
        L->data=element;
    }
}
//输出
void output(lstack L)
{
    if(L==NULL)
    {
        return;
    } else
    {
        lstack p=L;
        while(p!=NULL)
        {
            printf("%d\t",p->data);
            p=p->next;
        }
    }
    puts("");
}
//删除（尾删）
lstack delete(lstack L)
{
    if(L==NULL)
    {
        puts("stack is NULL");
        return NULL;
    } else if(L->next==NULL)
    {
        printf("delete element:%d\n",L->data);
        free(L);
        L=NULL;
    } else
    {
        lstack p=L->next;
        printf("delete element:%d\n",L->data);
        L->data=p->data;
        L->next=p->next;
        free(p);
        p=NULL;
    }
    return L;
}
int main() {
    lstack L=NULL;
    char str[10];
    int element;
    do {
        printf("please input element:");
        scanf("%d", &element);
        L= insert(L,element);
        printf("whether to continue y/n:");
        scanf("%s",str);
    }while(strcmp(str,"n"));
    puts("after insert:");
    output(L);
    do {
        L= delete(L);
        printf("whether to continue y/n:");
        scanf("%s",str);
    } while (strcmp(str,"n"));
    puts("after delete:");
    output(L);
    return 0;
}