loginfile>>username>>password;
cout<<"********************************************n*";
cout<<"  enter username        :                      ";
cin>>U;
cout<<"********************************************n*";
cout<<"  enter password                               ";
cin>>P;
cout<<"********************************************n*";
while(loginfile)
{
    if(username==U && password==P)
        cout<<"nwelcome player"<<endl;
    loginfile>>username>>password;
}
loginfile.close();