模拟题目所述的浏览器的各种操作，使用一个curWebsite变量来保存当前的Page。

/*Problem: 1028		User: DragonKnightMemory: 712K		Time: 79MSLanguage: G++		Result: Accepted*/#include 
    
     #include 
     
      #include 
      
       using namespace std;int main(){    string command, website;    stack
       
         back,forward;//前进栈，后退栈    string curWebsite = "http://www.acm.org/";//初始载入的页面    while(cin >> command)    {        if(command == "QUIT")        {            break;        }        else if(command == "VISIT")        {            cin >> website;            back.push(curWebsite);            curWebsite = website;            cout << curWebsite << endl;            while(!forward.empty()) forward.pop();        }        else if(command == "BACK")        {            if(!back.empty())            {                forward.push(curWebsite);                curWebsite = back.top();                back.pop();                cout << curWebsite << endl;            }            else            {                cout << "Ignored" << endl;            }        }        else if(command == "FORWARD")        {            if(!forward.empty())            {                back.push(curWebsite);                curWebsite = forward.top();                forward.pop();                cout << curWebsite << endl;            }            else            {                cout << "Ignored" << endl;            }        }    }    return 0;}