c语言堆栈链式存储结构

#include<stdio.h>
#include<stdlib.h>
#define ERROR 0
#define OK 1

typedef int ElementType;
typedef int Status;
struct SNode
{
    ElementType data;
    struct SNode *Next;
};
typedef struct SNode *Stack;

/**
 * 堆栈初始化，创建一个堆栈的头结点，指向null
 * */
Stack CreateStack()
{
    Stack S = (Stack)malloc(sizeof(struct SNode));
    S->Next = NULL;
    return S;
}

/**
 * 判断堆栈是否为空
 * */
Status IsEmpty(Stack S)
{
    if(S->Next == NULL)
        return OK;
    else
        return ERROR;  
}

/**
 * 将元素放入堆栈
 * */
void Push(Stack S,ElementType item)
{
    //1.先申请一块空间，存放数据
    Stack q = (Stack)malloc(sizeof(struct SNode));
    q->data = item;
    //2.然后把新生成的结点指向栈顶
    q->Next = S->Next;
    //3.在把栈顶指向新生成的结点
    S->Next = q;
}

/**
 * 删除栈顶元素
 * */
ElementType Pop(Stack S)
{
    //1.判断堆栈是否为空
    if(S->Next == NULL)
    {
        printf("堆栈满");
        return ERROR;
    }
    //2。A->B->C
    //删除A，把S->next 指向S->next->next;
    Stack p = S->Next;
    S->Next = p->Next;
    //3.保存A中的数据用于返回
    ElementType data = p->data;
    //4.free（A）
    free(p);
    return data;
}