program 66: working with linked lists using user defined functions

The need:
     This program is the same previous program written using User Defined Functions (UDFs). This program takes some numbers from the user stores them in nodes (creates linked list) and prints back for the user in the same order. So this program teaches us creating and accessing linked lists.

The code:  
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#include<stdio.h>
#include<stdlib.h>
struct node1
{
 int data;
 struct node1 *next;
};
typedef struct node1 node; //defining a datatype node
void printlist(node *p); //udf to print list
void add_node(int a,node *p); //udf to add node to last of list
node *create_node(int); //udf to create a new node
int main()
{
 int i,j;
 node *head; //head will be first node of list
 head=NULL; //initialising head to null
 printf("Enter numbers to be stored. enter -999 to end.\n");
 while(i!=-999) //this while loop takes the numbers and creates list
 { //loop runs untill user enters -999
  scanf("%d",&i);
  if(head==NULL) //if i is first node
  head=create_node(i); //creates a new node and assigns its address to head
  else
  add_node(i,head);
 }
 printf("All the  numbers has been entered into linked list.\n");
 printf("press any key to view the list\n");
 fflush(stdin); //to flush previous undesired inputs from keyboard
 getchar(); //to give a pause to program untill user press any key
 printf("\nThe list is\n\n");
 printlist(head); //UDF to print the linked list
 printf("\n");
 return 0;
}

void printlist(node *p)
{
 node *temp=p;
 while(temp->next!=NULL) //this loop prints the list
 {
  printf("%d-->",temp->data); //printing current member
  temp=temp->next; //jumping to next member in the list
 }
  printf("END");
}

void add_node(int a,node *p)
{
 node *temp1,*temp2;
 temp2=p;
 /*the case when temp1 is not first node, we have a list of some members.
   Its kind of a line of persons in which a newcomer has to stand at the last
   so we have to go to last position starting from first*/
 temp1=create_node(a);
 while(temp2->next!=NULL) //checking if temp2 is last node
  temp2=temp2->next; //loop exits if temp2 is last node
 temp2->next=temp1; //temp1 is appended to the list after last node
}

node *create_node(int b)
{
 node *temp1;
 temp1=(node*)malloc(sizeof(node)); //allocation of a temporary node
 temp1->data=b; //filling data in node
 temp1->next=NULL; /*making pointer to next location NULL
 because there is no next location till now*/
 return temp1; //return 
}

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The approach:  
The approach is very simple once you have read previous post. Everything has been written near statements as comments. Still this is a new topic so in case of any doubt please let me know. Now onward I'll use UDFs to do deal with linked lists.