Thread: ordered linked list

I get about 30 error messages. I know that there is a differnt way to wrote this linked like. This way i only get the error that NExt is not defined any ideas

Code:

 #include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#define Nlen    26

typedef struct person_t {
   char FName[Nlen];
   char LName[Nlen];
   char Sex;
   char Grade;
} PERSON;

void amend_file( char file[], PERSON *STU );
void show_file( char file[], PERSON *STU );

//Funstion to Ordered linked list
PERSON* InsertNode (PERSON *Top, PERSON *Node)
{
PERSON *Here, /* Node being compared to new node */  
*Prev; /* Node in front of Here node */
if (Top == NULL)/* List is empty – Place new node at top of list */
Top = Node;
else { /* Top != NULL *//* Start at Top of list */
Here = Top;
if ( Here->LName > Node->LName ) {/* Age less than first node’s age insert node at top of list */
Node->Next = Top;
Top = Node;
}
else {/* Search for place to insert new node */
Prev = Top;
Here = Prev->Next;
while ( (Here != NULL) &&
(Here->LName < Node->LName) ) {
Prev = Here;
Here = Here->Next;
}/* Insert into list at found spot */
Node->Next = Prev->Next;
Prev->Next = Node;
}
} /* end of Top != NULL */
return Top;
}

int main (void)
{
   PERSON *STU;
   int Ans;
   struct listNode  *start = NULL;         
	struct listNode  *last = NULL;    
	struct listNode  *data = NULL;
	struct listNode  *tempnode  = NULL;  
      char file[] = "data.txt";
    int Records [100];
    
    
  do
   {
      printf("\n\n"
             "1. Enter new record\n"
             "2. Display List\n"
             "3. Quit\n\n");
      printf("Prompt: ");
      fflush(stdout);
      if ( scanf("%d", &Ans) == 1 ) /* get answer */
      {
         STU = (PERSON*) malloc (sizeof (PERSON));
         if (STU == NULL)
         {
            perror("PERSON");
            exit(EXIT_FAILURE);
         }
         switch(Ans)
         {
            case 1:
               amend_file(file, STU);
              break;
            case 2:
               show_file(file, STU);
               break;
            case 3: default:
               Ans = 3;
               break;
         }
      } /* /get answer */
   }
    while ( Ans != 3 );
    
      fflush(stdout);
   free(STU);
   return EXIT_SUCCESS;
}
/*
* amend_file: Enter stuff into the working file.
* Very much a bare bones function so far; work on making this better
* Perhaps make it work with a linked list, as your struct suggests?
*/
void amend_file( char file[], PERSON *HEAD )
{
   assert(HEAD != NULL);
   FILE *fin = fopen(file, "a");
   if ( fin == NULL )
   {
      perror(file);
      exit(EXIT_FAILURE);
   }
   printf("Enter new record: ");
   printf ("\nEnter students First name ( up to %d letters):", Nlen);
   printf ("\nEnter students  Last name  ( up to %d letters):", Nlen);
   printf ("\nPlease enter Sex");
   printf ("\nPlease enter Grade\n");
   
   scanf("%s %s %c %c", HEAD->FName, HEAD->LName, &HEAD->Sex,
      &HEAD->Grade);
      
fprintf(fin, "%s %s %c %c\n", HEAD->LName, HEAD->FName, HEAD->Sex, HEAD->Grade);
     fflush(fin);
   fclose(fin);
}
/*
* show_file: Reads the working file.
* Bare bones again...
*/
void show_file ( char file[], PERSON *HEAD )
{
  assert(HEAD != NULL);
  int b = 1;
  FILE *fout = fopen(file, "r");
    
  if (file == NULL)
  {
    perror(file);
    exit(EXIT_FAILURE);
  }
   while (fscanf(fout, "%s %s %c %c", HEAD->FName, HEAD->LName, &HEAD->Sex,
     &HEAD->Grade) == 4)
  {
    printf("Record %d: %s %s %c %c\n", b, HEAD->FName, HEAD->LName,
       HEAD->Sex, HEAD->Grade);
    b++;
  }
  fclose(fout);
}