1. Definition and initialization of structure
2. The data space of the structure
3. Function parameters of structure
4. Linked list structure
4.1 One-way non-circular linked list
4.2 One-way circular linked list
4.3 Double Circular Linked List
5. Definition and operation of linked list
6. Add, delete, modify and check linked list
Increase: front insert and rear insert node
7. Sorting of linked list nodes
8. The release of the linked list
For the dynamically added linked list, the heap space needs to be released after use.
9. Save linked list data
Save the data of all nodes in the linked list (you can also directly see the linked list as a whole and write directly to the file)
Read the data of each node from the file
