I have a Neighborhood class and a House class. The Neighborhood class includes House.h because it needs to contain a vector<House>. But I also want each House to be able to answer "What neighborhood do you belong to?" I think I need to have a Neighborhood field for each House object, but if I include Neighborhood.h in House, I get an infinite loop of includes. So how could I go about getting House to know about Neighborhood without getting that loop of #includes?