How to sort classes

Question

How can we sort class values with heap sort

Answer 1

I hope I interpreted your question correctly as "How to sort objects of a class inside a heap?", because otherwise this won't be a help:
If we consider std::heap_sort() as an example, you can see that the function uses the '<' operator in order to compare the values to sort. You can view it here:
http://www.cplusplus.com/reference/algorithm/sort_heap/

Now you have two possibilities:
You can overload the '<' operator for your class and use that operator for the sort, or you create a function that takes in two objects of your class and returns which one should be considered 'smaller' or 'bigger', expressed as a boolean value, and give that function as an argument to your sorting function.
The point is, you have to provide a way for the compiler to decide how to compare your objects.