Hardcoding (may be a bit naff)

if (quest1 == true){level++;}
cout << "You have levelled up!\n";
cout << "Select which attributes you would like to increase.\n";

int choice = 0;
while choice(!=3)
cin >> choice;
{
switch(choice){
case 1:
{ cout << "Level up strength!\n";
strength++;
break;
}
case 2:{ cout << "Level up intelligence!\n";
intelligence++;
break;
}
case 3:{ cout << "Level up magic!\n";
magic++;
break;
}
default:
{ cout << "Invalid selection!\n";
break;
}
}
}