#include 
     
      #include 
      
       #include 
       
        #include 
        
         typedef struct Node{    int data;    struct Node * pNext;}NODE, * PNODE;typedef struct Stack{    PNODE pTop;    PNODE pBottom;}STACK, * PSTACK;     //PSTACK等价于struct STACK *void init(PSTACK); //初始化栈void push(PSTACK, int );  //压栈void traverse(PSTACK);    //遍历bool pop(PSTACK pS,int * pVal);   //出栈void clear(PSTACK pS);    //清空栈int main(void){    STACK S;  //STACK等价于struct Stack    int val;    init(&S);  //造出空栈        push(&S, 1);  //压栈    push(&S, 2);    push(&S, 3);    push(&S, 4);    push(&S, 5);    push(&S, 6);        traverse(&S); //遍历输出/*    if(pop(&S,&val))    {        printf("出栈成功，出栈的元素是%d\n", val);    }    else    {        printf("出栈失败！\n");    }*/        clear(&S);    traverse(&S);        return 0;}void init(PSTACK pS){    pS->pTop = (PNODE)malloc(sizeof(NODE));    if(NULL == pS->pTop)    {        printf("动态内存分配失败\n");        exit(-1);    }    else    {        pS->pBottom = pS->pTop;        pS->pTop->pNext = NULL;    }}void push(PSTACK pS, int val){    PNODE pNew = (PNODE)malloc(sizeof(NODE));  //创建新的节点    pNew->data = val;  //将val的值赋给新节点的数据域    pNew->pNext = pS->pTop; //将新节点的指针域指向下一个节点.pS->Top不能改写成pS->Bottom    pS->pTop = pNew; //pTop指向新节点    return;}void traverse(PSTACK pS){    PNODE p = pS->pTop;    while(p != pS->pBottom)    {        printf("%d ", p->data);        p = p->pNext;    }    printf("\n");    return;}bool empty(PSTACK pS){    if(pS->pTop == pS->pBottom)    {        return true;    }    else    {        return false;    }}bool pop(PSTACK pS,int * pVal){    if(empty(pS))    {        return false;    }    else    {        PNODE r = pS->pTop;        *pVal = r->data;        pS->pTop = r->pNext;        free(r);        r = NULL;        return true;    }}//清空栈void clear(PSTACK pS){    if(empty(pS))        //如果    {        return;    }    else    {        PNODE p = pS->pTop;  //定义元素p指向栈顶元素        PNODE q = NULL；     //定义元素q，初始值为空                while(p !=pS->pBottom)    //如果栈不为空        {            q = p->pNext;        //q指向p的下一个元素            free(p);            //释放p所指向的栈顶元素            p = q;               //将q所指向的元素赋给p        }        pS->pTop = pS->pBottom;          }}