Using an appropriate definition of ListNode, design a simple linked list class with only three member functions and a default constructor:

void add$($double x$)$;

boolean isMember$($double x$)$;

LinkedList$()$;

void printList$()$;

The add function adds a new node containing x to the front $($head$)$ of the list, while the isMember function tests to see if the list contains a node with the value x$.$ The printList function should print the numbers in the list beginning with the front $($head$)$ value.

In the main function, test your linked list class by adding various numbers to the list and then testing for membership. Also, add some numbers, print the list, then add more numbers and print the list again.