Adapting generic code to different size of linked list in C

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For a programming assignment, we've been asked to read in some data from a text file and populate a linked list with the data. Here is the example code we've been given:

#include <stdio.h>
#include <stdlib.h>
#include <assert.h>

#define MAX_INPUT 20
#define EXTRA_CHARS 2

typedef struct listNode
{
   int data;
   struct listNode * next;
} ListNode;

typedef ListNode * ListNodePtr;

int main()
{
   ListNodePtr head, new, current, previous, next;
   unsigned listSize;

   int i, anInt;
   char str[MAX_INPUT];

   listSize = 0;
   head = NULL;

   while (fgets(str, MAX_INPUT+EXTRA_CHARS, stdin) != NULL)
   {
      /* Parsing the string to int */
      if(sscanf(str,"%d",&anInt) != 1)
      {
         sprintf(str, "Invalid input entered \n");
         exit(EXIT_FAILURE);
      }

      /* Creating the node using malloc(...) */

      if ( (new=malloc(sizeof(ListNode))) == NULL)
      {  
         fprintf(stderr,"\nMemory Allocation for ListInsert failed!\n");
         fprintf(stderr,"Aborting data entry!\n");
         break;
      }

      current = head;
      previous = NULL;
      /* Search to find where in insert new list node */
      while (current != NULL && current->data < anInt)
      {
         previous = current;
         current = current->next;
      }

      new->data = anInt;
      new->next = current;
      listSize++;

      if (previous == NULL)
      {
         head = new;
      }
      else
      {
         previous->next = new;
      }
   }/*End of input loop */

   /* Display integers in linked list */
   current = head;
   while (current != NULL)
   {
      printf("%d\n", current->data);
      current = current->next;
   }

   /* Deallocate memory used by list nodes */
   current = head;
   while (current != NULL)
   {
      next = current->next;
      free(current);
      current = next;
   }

   return EXIT_SUCCESS;
}

Here's the problem I have with it. In EVERY example of linked lists I've seen online or in books, the definition of a linked list is given as a struct that contains only one item of data and a pointer to the next node in the list. The problem is that we've been given the following structure definitions to populate with data:

typedef struct price
{
   unsigned dollars;
   unsigned cents;
} PriceType;

typedef struct item
{
   char itemID[ID_LEN + 1];
   char itemName[MAX_NAME_LEN + 1];
   PriceType prices[NUM_PRICES];
   char itemDescription[MAX_DESC_LEN + 1];
   ItemTypePtr nextItem;
} ItemType;

typedef struct category
{
   char categoryID[ID_LEN + 1];
   char categoryName[MAX_NAME_LEN + 1];
   char drinkType;      /* (H)ot or (C)old. */
   char categoryDescription[MAX_DESC_LEN + 1];
   CategoryTypePtr nextCategory;
   ItemTypePtr headItem;
   unsigned numItems;
} CategoryType;

typedef struct bcs
{
   CategoryTypePtr headCategory; /* Pointer to the next node */
   unsigned numCategories;
} BCSType;

This does not fit in with all the examples I've seen. So in the "generic" code above, do I have to do everything above, but replace the "new->data" part with, for example, "category->categoryID", and "category->categoryName" etc etc for all the members of the struct in order to populate the entire linked list with data?

asked 2 mins ago

LeeCarbusier

1

Adapting generic code to different size of linked list in C