#define TRUE 1
#define FALSE 0
#define OK 1
#define ERROR 0
#define INFEASIBLE -1
#define OVERFLOW -2
typedef int Status;
typedef int SElemType;

typedef struct StackNode{
    SElemType data;
    struct StackNode *next;
}StackNode,*LinkStack; 

// 构造空栈
Status InitStack(LinkStack &S)
{
    S = NULL;
    return OK;
} 
// 销毁栈 
Status DestroyStack(LinkStack &S)
{
    S = NULL;
    free(S);
    return OK;
}
// 清空栈
Status ClearStack(LinkStack &S)
{
    S = NULL;
    return OK;
}
// 判断栈是否为空
Status StackEmpty(LinkStack S)
{
    if(!S) return TRUE;
    return ERROR;
}
// 获取栈的长度
int StackLength(LinkStack S)
{
    return 0;
 } 
// 获取栈顶元素
Status GetTop(LinkStack S,SElemType &e)
{
    if(S != NULL)
    e = S->data;
    return OK;    
}
// 插入元素
Status Push(LinkStack &S,SElemType e)
{
    LinkStack p = (LinkStack)malloc(sizeof(StackNode));
    p->data = e;
    p->next = S;
    S = p;
    return OK;
}
// 删除栈顶元素，并用e返回其值w
Status Pop(LinkStack &S,SElemType &e)
{
    if(S == NULL) return ERROR;
    e = S->data;
    LinkStack p = (LinkStack)malloc(sizeof(StackNode));
    p = S;
    S = S->next;
    free(p);
    return OK;
}

测试

int main()
{
    LinkStack S;
    InitStack(S);
    Push(S,1);
    Push(S,2);
    int e;
    GetTop(S,e);
    printf("%d\n",e);
    Pop(S,e);
    printf("%d\n",e);
    GetTop(S,e);
    printf("%d\n",e);
    
    return 0;
}