typedef struct SNode *Stack;

struct SNode{

ElementType Data;

struct SNode *Next; 

}; 

Stack　CreateStack()

{//构建一个堆栈的头结点，返回指针 

Stack S;

S=(Stack)malloc(sizeof(struct SNode));

S->Next=NULL;

return S;

}

int IsEmpty(Stack S)

{//判断堆栈S是否为空，若为空函数返回整数1，否则返回0 

return (S->Next=NULL);

} 

void Push(ElementType item,Stack S)

{//将元素item压入堆栈S 

struct SNode *TmpCell;

TmpCell=(struct SNode *)malloc(sizeof(struct SNode));

TmpCell->Element=item;

TmpCell->Next=S->Next;

S->Next=TmpCell;

}

ElementType Pop(Stack S)

{//删除并返回堆栈S的栈顶元素 

struct SNode *FirstCell;

ElementType TopElem;

if(IsEmpty(s)) {

printf("堆栈空")； return NULL;

}else{

FirstCell=S->Next;

S->Next=FirstCell->Next;

TopElem=FirstCell->Element;

free(FirstCell);

return TopElem;

}

}