#include<stdio.h>
#include<stdio.h>
#include<stdlib.h>


typedef struct Node{
    int data;
    struct Node * pNext;
}NODE,*PNODE;


typedef struct Stack{
    PNODE pTop;
    PNODE pBottom;
}STACK,*PSTACK;


//函数声明
void init(PSTACK pS);//初始化
void push(PSTACK pS,int val);//压栈
void traverse(PSTACK);//遍历输出
bool empty(PSTACK pS);//判断栈是否为空
bool pop(PSTACK,int *); //出栈
void clear(PSTACK pS);//清空栈


int main(void){
    STACK S;
    int val=0;
    init(&S); //完成初始化 ,目的就是造出一个空栈
    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,出栈的数是%d\n",&val);     
    }
    else{
        printf("出栈失败!\n");
    }
    traverse(&S);//遍历输出
    clear(&S);
    traverse(&S);//遍历输出
    return 0;
}


//初始化
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;
    }
}


//压栈
void push(PSTACK pS,int val){
    PNODE pNew=(PNODE)malloc(sizeof(NODE));//动态造出一个新的结点
    pNew->data=val;//把val放到新结点pNew的数据域中
    pNew->pNext=pS->pTop; //不能改成pS->pBottom
    pS->pTop=pNew; //使pS->pTop指向新的结点pNew
    return;
}


//遍历输出
void traverse(PSTACK pS){
    PNODE p=pS->pTop;
    while(p!=pS->pBottom){
        printf("%d\t",p->data);
        p=p->pNext;
    }
    printf("\n");
    return;
}


//判断栈是否为空
bool empty(PSTACK pS){
    if(pS->pTop==pS->pBottom){
        return true;
    }
    else{
        return false;
    }
}


//出栈
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)){
        return;
    }
    else{
        PNODE p=pS->pTop;
        PNODE q=NULL;
        while(p!=pS->pBottom){
            q=p->pNext;
            free(p);
            p=q;
        }
        pS->pTop=pS->pBottom;
    }
}

printf("出栈成功,出栈的数是%d\n",&val);

谢谢指导