Write a C Program to find the number of data in a linked list

#include <stdio.h>
#define newnode (struct node*)malloc(sizeof(struct node))

typedef struct node
{
 int data;
 struct node *next;
} node;

node *create_list();

void main()
{
    node *f;
 int len;
 f = NULL;

 f = create_list();
 len = find_len(f);
 printf("\n length = %d",len);
} // main

node *create_list()
{
 node *f,*c,*p;
 int tdata;
 f = NULL;
 printf("\n Enter data ( use 0 to exit ) : ");
 scanf("%d",&tdata);
 while( tdata != 0 )
 {
  c = newnode;
  if( c == NULL)
  {
   printf("\n Insuf. mem. ");
   exit(0);
  }
  c->data = tdata;
  c->next = NULL;
  if( f== NULL)
   f = c;
  else
   p->next = c;
   p = c;
   printf("\n Enter data ( use 0 to exit ) : ");
   scanf("%d",&tdata);
 } //while
 return(f);
} // create list

int find_len(node *f)
{
 int len=0;
 node *t;
 if( f == NULL)
 return(0);
 t = f;
 while( t != NULL )
 {
  len++;
  t = t->next;
 }
 return(len);
}

/*
Summary: Linked list is an ordered set of data elements, each containing a link to its successor. This program is to create a linked list. After creating the linked list ,the length of linked list is calculated.
*/