Which style of return should I use?

Question

This is related to conventions used in C#.

I've got a method that has two parameters (X and Y coordinates). These coordinates represent the position at which a "tile" may reside. If a tile resides at these coordinates, the method returns its number. If no tile resides at these coordinates, I'm wondering how the method should behave.

I see three options:

1. Use exceptions. I may raise an exception every time Method finds no tile. However, as this situation is not rare, this option is the worst one.
2. Do it the old fashioned C++ way and return -1 if there is no tile.
3. Make the tile number a reference parameter and change the return type of method to boolean to show whether there is a tile or not. But this seems a bit complicated to me.

So, what should I do?

Answer 1

You can return null, and check for this on the calling code.

Of course you'd have to use a nullable type:

int? i = YourMethodHere(x, y);