Each element in the node linked list is called a "node", and each node should include two parts: one is the actual data needed by the user; the other is the address of the previous or next node, that is, the pointer field
and data fields. Each data node in the data structure corresponds to a storage unit, and this storage unit is called a storage node, or simply a node.
Header element
The first data element in the linear table
Footer element
The last data element in the linear list
Head node
The head node refers to the node in the linked list that stores the first data element a1 in the linear list.
Head node
Attach a node before the first node (head node) of the linked list. The effect is that when using related linked list programming, the empty list and non-empty list can not be considered separately, so that the program is simple and efficient.
