程序清单3.7 课本44页

#include<iostream>
using namespace std;
int main()
{
cout<<"\aOperation\"HyperHype\" is now activated!\n";
cout<<"Enter your agent code：_______\b\b\b\b\b\b\b";
long code;
cin>>code;
cout<<"\aYou entered "<<code<<"...\n";
cout<<"\aCode verified! Proceed with Plan 23!\n";
system("pause");
return 0;
}

/* \a表示振铃，\b表示退格，\n表示换行