Linked list with multiple parent and child nodes

Question

I am trying to design a program that takes in data from a file, after which it gives numbering to unique data, linked list also contains parent and child lists.

Data

Answer 1

Is it possible to create linked list with nodes with more than one next or more than one previous nodes, if so how would the struct look like?

Yes it is possible -- the question you must ask yourself is "how do I store an aribitrarily large amount of data?", the brief answer being "you must use an ADT". Recall that an ADT is a mathematical model for a collection of data.

You can implement it with any ADT, the choice of the specific ADT depends on the operations you plan to use most frequently. For my example, I will use a dynamic array. The structure would be declared as follows (omitting the specific fields for the node):

struct llnode {
  int item;
  struct llnode *children;
  int length;
  int capacity;
};

... where the item is the ASCII code for 'A', 'B', 'C', etc. and children is a pointer to an array of struct llnodes. You can however create a separate structure for a dynamic array to be less messy however it is entirely up to you. The same idea would apply to the parent nodes.