How to make C++ template stack work with basic data types and compound variables?

Question

Templates are nice for similar algorithms of different data types. Say I make a template stack of a basic data type...

Stack<int> stck(10);
stck.Push(5);

I'd pop it...

int x = stck.Pop();

x would be 5. If I call pop again, there are no items, so I have the method just return 0 for null. It could be something else, but whatever.

But now, if I change the template type to a compound variable (a structure type - say, RECT), and the stack is empty, it can't return 0. It expects a RECT type, but I don't have any left. How do I make this work for basic data types and compound variables? Exceptions?

Answer 1

3 options

make popping en emtpy stack undefined and don't worry about it

throw an exception

return default constructed T() (which happens to be 0 for the numeric types)