When working with lists, there seem to be certain items of information
about the list that is common. Some of these things are:
Number of nodes in a list
A total of some values in the list
The head of the list
Sometimes we need to know the tail of the list
etc.
It is quite common to have another type of struct that holds this
information about the list. It can increasse efficiency in the program
by always keeping a total of some data members, etc.
Here's an example:
/* nodePtr */
typedef struct tag *nodePtr;
/* node */
typedef struct tag
{
int data;
nodePtr next;
}node;
/* Struct to keep info about the list */
typedef struct dummy
{
int numNodes;
int dataTotal;
nodePtr head;
nodePtr tail;
} listInfo;