Linked list node with pointer to struct in C

Question

I am new to C programming. Familiarising muself with struct pointers and linekd lists. I came across concept of linked list node with pointer to struct.

typedef struct
{
   string name, surname;
   int matriculation_num;
}Student_typedef;

typedef struct
{
   Tstudent* student;
   Node_typedef* next;
} Node_typedef;

Can anyone tell me what exactly is the purpose of Node_typedef. Where are such implementations usefull ? Any useful link is much appreciated.

Answer 1

The two shown struct type definitions separate the stored data from the storing mechanism.

You can see that Student_typedef has only members which relate to information to store, but none relating to storing. The goal is to have a mechanism which can store a multitude of this data structure.

On the other hand Node_typedef does not contain any of the information to store, only a single pointer to the complete data. If the structure of the inforamtion to store would change (though still be reflected by the same type identifier Student_typedef ), then nothing about this storage mechanism would have to be changed.

Or to describe it from a different angle, two developers working on a student database would only have to agree that all the needed information for each student is inside Student_typedef . Then one developer could handle programming functions to enter or edit a given struct (based on a pointer to the struct provided by the storage), while the other developer could handle storage aspects, like adding a new struct to fill, deleting, optimising memory, etc.

Such methods of interface definition and abstraction of code parts are necessary for efficiently handling large projects.