Class.h is having issues with virtual functions

[snickbobbit]

I'm writing a class "Property" for a program that manages different types of properties. This is my .h for y base class. I was trying to write a virtual void function to convert different children classes to strings that can be displayed, but Xcode is freaking out.

I had it as:

virtual void toString()= 0;

and it gave me an error message: "Virtual can only exist in non-static member functions" and "field has incomplete type 'void'"

I changed it to:

virtual string toString() = 0;

and the error message didn't change.

Is this an issue with Xcode or did I do something wrong? Even after changing it to string it told me that it "has incomplete type 'void'"
Any ideas?

[MiiNiPaa]

Paste whole class definition here. There is too little information to say what is wrong.