62     void insertAfter(NODE* node, NODE* newNode) {  in insertAfter()  argument
63         newNode->prev = node;  in insertAfter()
64         newNode->next = node->next;  in insertAfter()
65         if (node->next == nullptr) mLast = newNode;  in insertAfter()
66         else                 node->next->prev = newNode;  in insertAfter()
67         node->next = newNode;  in insertAfter()
70     void insertBefore(NODE* node, NODE* newNode) {  in insertBefore()  argument
71          newNode->prev = node->prev;  in insertBefore()
72          newNode->next = node;  in insertBefore()
73          if (node->prev == nullptr)   mFirst = newNode;  in insertBefore()
74          else                   node->prev->next = newNode;  in insertBefore()
75          node->prev = newNode;  in insertBefore()
78     void insertHead(NODE* newNode) {  in insertHead()  argument
80             mFirst = mLast = newNode;  in insertHead()
81             newNode->prev = newNode->next = nullptr;  in insertHead()
83             newNode->prev = nullptr;  in insertHead()
84             newNode->next = mFirst;  in insertHead()
85             mFirst->prev = newNode;  in insertHead()
86             mFirst = newNode;  in insertHead()
90     void insertTail(NODE* newNode) {  in insertTail()  argument
92             insertHead(newNode);  in insertTail()
94             newNode->prev = mLast;  in insertTail()
95             newNode->next = 0;  in insertTail()
96             mLast->next = newNode;  in insertTail()
97             mLast = newNode;  in insertTail()