poj1028--Web Navigation

  这道题目的算法题中已经给出来，就是利用两个栈来协同工作，用笔在纸上模拟一翻就可以得出答案，注意的是遇到VISIT操作的时候，最后一步要清空Forward栈。

  // Web Navigation.cpp : Defines the entry point for the console application.//#include "stdafx.h"#include<iostream>#include<fstream>#include<algorithm>#include<stack>#include<string>using namespace std;int _tmain(int argc, _TCHAR* argv[]){ifstream cin("d://1.txt");stack<string> back,forward;string s,current="http://www.acm.org/";while(1){getline(cin,s);if(s=="QUIT") break;if(s.length()>7){back.push(current);current=s.substr(6);cout<<current<<endl;while(!forward.empty())forward.pop();}else if(s=="BACK"){if(back.empty())cout<<"Ignored"<<endl;else{forward.push(current);current=back.top();back.pop();cout<<current<<endl;}}else if(s=="FORWARD"){if(forward.empty())cout<<"Ignored"<<endl;else{back.push(current);current=forward.top();forward.pop();cout<<current<<endl;}}}system("pause");return 0;}