Why should pop() take an argument?

Question

Quick background
I\'m a Java developer who\'s been playing around with C++ in my free/bored time.

Preface
In C++, you often see

Answer 1

Using C++0x makes the whole thing hard again.

As

stack.pop(item); // move top data to item without copying

makes it possible to efficiently move the top element from the stack. Whereas

item = stack.top(); // make a copy of the top element
stack.pop(); // delete top element

doesn't allow such optimizations.