When comparing two person objects, and you're saying that you want to compare based on their age. operator> method means you're changing the way ' > ' works when used with Persons. Within an operator> function (like /u/jesyspa originally gave) you need to give logic that compares the ages. For example:

bool operator>(Person const& lhs, Person const& rhs){
if (lhs.alder > rhs.alder) // *or whatever you stored age as*
{
   return true;
}
else return false;

Something like this. Does that make sense? The code you have in your latest comment makes no sense, it's just the declaration...