This is my own small module, used to implement the basic operations of the two-way linked list, I don't know if it is the best algorithm, I hope everyone will give more opinions.
Let's define two data structures:
Typedef struct MNG
{
INT longth; / * Length of the list * /
LTBL * TOP; / * Pointer to the linked table * /
} Mng;
Typedef struct ltdl
{
LTBL * fp;
}