#include <bits/stdc++.h>
using namespace std;

const int MaxSize = 100000;

typedef char ElemType;

typedef struct{
	ElemType data[MaxSize];
	int top;
}SqStack;

void InitStack(SqStack *& s){
	s = (SqStack * )malloc(sizeof(SqStack));
	s -> top = -1;
}  

void DestoryStack(SqStack *& s){
	free(s);
}

bool StackEmpty(SqStack * s){
	return (s -> top == -1);
}

bool Push(SqStack *& s, ElemType e){
	if(s -> top == MaxSize - 1) return false;
	s -> top ++;
	s -> data[s -> top] = e;
	return true;
}

bool Pop(SqStack *& s, ElemType &e){
	if(s -> top == -1) return false;
	e = s -> data[s -> top];
	s -> top --;
	return true;
}

bool GetTop(SqStack *s, ElemType &e){
	if(s -> top == -1) return false;
	e = s -> data[s -> top];
	return true;
}


int main(){  
	SqStack *s;
	InitStack(s);
	for(char i = 'a'; i <= 'e'; ++i) Push(s, i);
	if(StackEmpty(s)) cout << "空的" << endl;
	else cout << "不是空的" << endl;
	puts("輸出棧");
	while(!StackEmpty(s)){
		char e;
		Pop(s, e);
		printf("%c\n", e);
	}                   
	if(StackEmpty(s)) cout << "空的" << endl;
	else cout << "不是空的" << endl;
	DestoryStack(s);                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      
	return 0;
}