Given the following class:

class StringNode

{

public:

string elem;

stringNode* next;

stringNode* prev;

};

Write the function that would add a node to the end of the list. The function should be named AddToEnd. You can assume that two pointers, head and tail, have been declared and initialized to NULL before the first node is ever added. You can, also, assume that an Empty function has been implemented and works (if needed) to test if the list is empty. This list is not circular.