title: Member function vs. nonmember function?
body: <p>What is your rule for which functions that operate on a class should be member functions vs. nonmember functions?
  For example, I have a class which represents a maze using a matrix of bools. I am making a function called isConnected which verifies that 2 points in the maze are in the same region (i.e. it is possible to travel from A to B).</p>
  
  <p>Should this be member or nonmember? What is a good rule?</p>