Discards qualifiers error

Question

For my compsci class, I am implementing a Stack template class, but have run into an odd error:

Stack.h: In member function ‘const T Stack

Answer 1

You cannot call a non-const method from a const method. That would 'discard' the const qualifier.

Basically it means that if it allowed you to call the method, then it could change the object, and that would break the promise of not modifying the object that the const at the end of the method signature offers.