#include????//C++文件輸入輸出流
??//字符串操作
#include???//C++標準輸入輸出
#include??//實現將char[]轉換成string的功能頭文件
#include
#include?

using?namespace?std;

typedef?struct?stacknode???
{
	char?data[70];
	struct?stacknode?*next;
}stacknode;

void?push（stacknode?*top?string?e）????????????//進棧
{
	stacknode?*q;
	q=（stacknode*）malloc（sizeof（stacknode））;
	strcpy（q->datae.c_str（））;???//e.c_str（）庫函數實現將string類型的e轉換成char[]類型
	q->next=top->next;???????????//strcpy庫函數實現將轉換后的e.str（）復制到q->data中
	top->next=q;
}

string?pop（stacknode?*top）???????????//出棧
{?
	stacknode?*p;
	char?e[70];
	if（top->next==NULL）?
	{?
		return?NULL;?
	}
	else
	{
		p?=?top->next;
		top->next?=?p->next;
		strcpy（ep->data）;
		free（p）;
		//strstream?s;???????//將char