栈结构实现

#define  _CRT_SECURE_NO_WARNINGS
#include<stdio.h>
#include<string.h>
#include<stdlib.h>
#include<stdbool.h>


typedef struct Stack      //定义栈模型
{
	PNODE TOP;
	PNODE BUTTOM;
}*PSTACK,STACK;

/*
栈定义的模型
初始化方法，压入栈的方法，出栈的方法，遍历的方法，
*/
//初始化栈的操作
void init_stack(PSTACK);
//压入栈
void push_stack(PSTACK, int);
//出栈
void pop_stack(PSTACK, int*);
//遍历
void traverse(PSTACK);
//是否为空
bool empty(PSTACK);
//clear;
void clear(PSTACK);

/*
实现上述栈的函数
*/
//初始化
void init_stack(PSTACK phead){
	PNODE stack = (PNODE)malloc(sizeof(NODE));
	if (stack == NULL){
		printf("创建失败！");
		return ;
	}
	phead->BUTTOM = stack;
	phead->TOP = phead->BUTTOM;
	phead->TOP->next = NULL;

}
//入栈
void push_stack(PSTACK phead, int val){
	PNODE pnew = (PNODE)malloc(sizeof(NODE));
	pnew->data = val;
	pnew->next = phead->TOP;
	phead->TOP = pnew;
}
//出栈
void pop_stack(PSTACK phead, int *val){
	if (empty(phead))
	{
		return;
	}
	PNODE p = phead->TOP;
	*val = p->data;
	phead->TOP = p->next;
	free(p);
	p = NULL;
}
//遍历
void traverse(PSTACK phead){
	PNODE p = phead->TOP;
	while (phead->BUTTOM!=p)
	{
		printf("%d", p->data);
		p = p->next;
	}
}
//是否为空
bool empty(PSTACK phead){
	if (phead->BUTTOM == phead->TOP)
		return true;
	return false;
}
//clear
void clear(PSTACK phead){
	if (empty(phead))
		return;
	PNODE p = phead->TOP;
	while (p != phead->BUTTOM)
	{
		phead->TOP = p->next;
		free(p);
		p = phead->TOP;
	}
}

void main(){
	STACK stack;
	int val;
	init_stack(&stack);   //初始化
	if (empty(&stack))  //
		printf("空stack\n");
	push_stack(&stack, 1);//push
	push_stack(&stack, 2);
	push_stack(&stack, 3);
	traverse(&stack);   //遍历
	pop_stack(&stack, &val);
	clear(&stack);  //clear
	pop_stack(&stack, &val);
	printf("%d", val);
	pop_stack(&stack, &val);
	pop_stack(&stack,&val);   //pop
	system("pause");
}