LLNode* dequeue(){
LLNode* temp_front = front;
front = front->getNext();
if(front == back)
back = back->getNext();
return temp_front;
}
void display(){
LLNode* temp = front;
while(temp){
std::cout << temp->getData() << " ";
temp = temp->getNext();
}
std::cout << std::endl;
}
