handwrite the solution please c++

2. Wanita wrote code to implement a queue using a linked list. The code starts: struct QNode { double val; QNode *next; }; class My Queue { QNode * front; // points to oldest item QNode * back; // points to most recent insert MyQueue ( ) : front(nullptr), back(nullptr) { } Give suitable code for a de-queue function that removes the value from the front of the list and returns it to the user: const double UNDERFLOW = -999.999; double MyQueue::de_queue( ) {