I almost completed a implementation of  a singly-linked-list.
- Ran into trouble when I realized my peek() function was changing
the head of the list. Solved it by having another pointer to the
head of the list.
- Learned that MyClass() gives you a MyClass, new MyClass() gives
you a MyClass* .
- The operator delete is useful for deallocating the memory block previously
allocated by a call to the operator new.
- struct is an easy way of making all components of a class (fields+functions)
    private by default.
    - Still need to implement insertAfter and removeAfter.