再回首，数据结构——链栈上的常见操作

       最近在复习数据结构，顺便看看大一的时候写的代码，看完之后比当初有了更加深刻的体会。
 
       希望这些能提供给初学者一些参考。

//栈的链式存储结构
typedef struct snode
{
ElementType data;
struct snode *next;
}StackNode;

typedef StackNode *LinkStack;

//初始化栈
LinkStack StackInit()
{
s = (LinkStack)malloc(sizeof(StackNode)); //建立链栈的头结点
s->next == NULL;
return s;
}

//判断栈s是否为空StackEmpty(s)
int StackEmpty(LinkStack s)
{
return (!(s->next));
}

//求栈的长度StackLength(s)
int StackLength(LinkStack s)
{
p = s->next;
length = 0;
while (p)
{
length++;
p = p->next;
}
return length;
}

//获取栈顶元素的值GetTop(s)
Element GetTop(LinkStack s)
{
if (StackEmpty(s))
return nil;
return s->next->data;
}

//进栈Push(s, e)
void Push(LinkStack s, ElementType e)
{
p = (StackNode*)malloc(sizeof(StackNode));
p->data = e;
p->next = s->next;
s->next = p;
}

//出栈 Pop(s)
ElementType Pop (LinkStack s)
{
if (StackEmpty(s))
return nil;
e = s->next->data;
p = s->next;
s->next = p->next;
free(p);
return e;
}