C++ :: Creating Function That Outputs Either 1 Or 0 Depending On Input After Checking

I am trying to simplify my code by creating a function which takes an input then checks whether it is "y" or "n" then outputs either 1 or 0 depending on the input. So far this is what I have

int Choice(string choice) {
while(choice.compare("n") != 0 && choice.compare("N") != 0 && choice.compare("y") != 0 && choice.compare("Y") != 0){
cout << "Please enter a valid input either [y/n] : " << endl;
cin.clear(); cin.ignore(); cin >> choice;

[Code] ...

And I call it in the program using

cout << "Do you wish to change the hubble type of any galaxies? [y/n]" << endl;
cin >> choice;
while(Choice(choice) == 1){
....
cout << "Do you wish to change the hubble type of another galaxy? [y/n]" << endl;
cin << choice;
}

It compiles fine but displays some bizarre behaviour, I need to end the line twice in order for the program to continue and sometimes it just stops working (doesn't exit just appears to be stuck in a loop).