#include <iostream>
using namespace std;

const int N = 100;
struct CStack
{
    char s[N]; //栈的内容保存在s中
    int tp;		//栈顶指示器，栈空为－1
};

void init(CStack* stk)
{
    stk->tp = -1;
}

bool isEmpty(CStack stk)
{
    return (stk.tp==-1);
}

bool isFull(CStack stk)
{
    return (stk.tp==(N-1));
}

void push(CStack* stk, char c)
{
    stk->tp++;
    stk->s[stk->tp] = c;
}

char pop(CStack* stk)
{
    int oldtp = stk->tp;
    stk->tp--;
    return (stk->s[oldtp]);
}

char top(CStack stk)
{
    return (stk.s[stk.tp]);
}

int main()
{
	char str[] = {"0123456789"};
	struct CStack s;

	cout << str << endl;
	init(&s);

	int i = 0;
	while(str[i] && !isFull(s))
		push(&s, str[i++]);
	while(!isEmpty(s))
		cout << pop(&s);
	cout << endl;
}