栈的四则运算实现及详解

#include <stdio.h>  
#include <stdlib.h>  
 
typedef enum Status
{
ERROR = 0, OK = 1
}Status;

typedef int ElemType;

typedef struct StackNode  
{  
    ElemType data;  
    struct StackNode *next;  
}StackNode, *LinkStackPtr;  
  
typedef struct linkStack  
{  
    LinkStackPtr top;     //栈顶指针
    int count;            //栈中元素个数
}LinkStack;  
  
Status initLStack(LinkStack *s)  
{  
    s->top = NULL;  
    s->count = 0;  
    return OK;  
}  

Status isEmptyLStack(LinkStack *s)  //判断链表是否为空

{
if (s->count == 0)
{
return OK;
}
else
{
return ERROR;
}
}
  
Status pushLStack(LinkStack *s, ElemType datas)    //入栈 
{  
    StackNode *p = (StackNode *)malloc(sizeof(StackNode));  
    if(p == NULL)  
    {  
        return ERROR;  
    }  
    p->data = datas;  
    p->next = s->top;  
    s->top = p;  
    s->count++;  
    return OK;  
}  
  
int getTopLStack(LinkStack *s)            //获取链表头元素 
{  
    if(NULL == s->top)  
    {  
        return ERROR;