Assume that a singly linked list is implemented with a header node, but no tail node, and that it maintains only a reference to the header node. Write a class that includes methods to
a. Return the size of the linked list
b. Print the linked list
c. Test if a value x is contained in the linked list
d. Add a value x if it is not already contained in the linked list
e. Remove a value x if it is contained in the linked list