1) What is an ADT? What does a class need in order to be an ADT?
2) Suppose we could separate the class definitions and class implementation
in two different files from the main program. What are the things
we should be considering when we make such separate files? How do
you think one part of the program will learn about things that are defined
in another part?
3) What was the use of using namespace std; in your programs?