//Dec 12 2009
#include<iostream>
#include<string>
using namespace std;
int main()
{
	string command,URL,fstack[101],bstack[101],curent_page;
	curent_page="http://www.acm.org/";
	int bp=-1,fp=-1;
	while(cin>>command)
	{
		if(command=="VISIT")
		{
			cin>>URL;
			bstack[++bp]=curent_page;
			curent_page=URL;
			fp=-1;
			cout<<curent_page<<endl;
		}
		else if(command=="BACK")
		{
			if(bp==-1)
				cout<<"Ignored"<<endl;
			else 
			{
				fstack[++fp]=curent_page;
				curent_page=bstack[bp--];
				cout<<curent_page<<endl;
			}
		}
		else if(command=="FORWARD")
		{
			if(fp==-1)
				cout<<"Ignored"<<endl;
			else
			{
				bstack[++bp]=curent_page;
				curent_page=fstack[fp--];
				cout<<curent_page<<endl;
			}
		}
		else  if(command=="QUIT")
			break;
	}
	return 0;
}

• Re:一次AC代码 (912) 0810xk 2010-01-06 21:18:14