Basic Structure
In this lab you will use a linked list to practice using dynamic memory.
Your assignment is to finish implementing three of the member functions of the class List: insert(), remove() and size().
The linked list provided is a linked list of ints. It keeps the list in sorted order. There is a dummy node, called m_head, that is always present in the list. This node contains no data and is not actually considered an element. It is simply there to provide as a placeholder.