Introduction - If you have any usage issues, please Google them yourself
Initialized double-linked list H (H is single-chain head pointer)
Insert the five-character elements a , b , c , d , e in turn
Output double linked list H
Outputs the length of double-linked list H
Determine if the double-linked list H is empty
Outputs the third element of the double-linked list H
Outputs the position of the character element d in double-linked list H
插 Insert the character element f at the fourth element position
Output double linked list H
Delete the third element of double-linked list H
Output double linked list H
Release and destroy the double linked list H