Creating and Deleting nodes in a Linked List in C

#include <stdio.h>
#include <conio.h>
#include <malloc.h>
#include <windows.h>
/* structure containing a data part and link part */
struct node
{
 int data ;
 struct node * link ;
} ;
void append ( struct node **, int ) ;
void addatbeg ( struct node **, int ) ;
void addafter ( struct node *, int, int ) ;
void display ( struct node * ) ;
int count ( struct node * ) ;
void del ( struct node **, int ) ;
int main( )
{
 struct node *p ;
 p = NULL ;  /* empty linked list */
 printf ( "No. of elements in the Linked List = %d\n", count ( p ) ) ;
 append ( &p, 14 ) ;
 append ( &p, 30 ) ;
 append ( &p, 25 ) ;
 append ( &p, 42 ) ;
 append ( &p, 17 ) ;
 system ( "cls" ) ;
 display ( p ) ;
 addatbeg ( &p, 999 ) ;
 addatbeg ( &p, 888 ) ;
 addatbeg ( &p, 777 ) ;
 display ( p ) ;
 addafter ( p, 7, 0 ) ;
 addafter ( p, 2, 1 ) ;
 addafter ( p, 5, 99 ) ;
 display ( p ) ;
 printf ( "No. of elements in the Linked List = %d\n", count ( p ) ) ;
 del ( &p, 99 ) ;
 del ( &p, 1 ) ;
 del ( &p, 10 ) ;
 display ( p ) ;
 printf ( "No. of elements in the linked list = %d\n", count ( p ) ) ;
 return 0 ;
}
/* adds a node at the end of a linked list */
void append ( struct node **q, int num )
{
 struct node *temp, *r ;
 if ( *q == NULL )  /* if the list is empty, create first node */
 {
  temp = ( struct node * ) malloc ( sizeof ( struct node ) ) ;
  temp -> data = num ;
  temp -> link = NULL ;
  *q = temp ;
 }
 else
 {
  temp = *q ;
  /* go to last node */
  while ( temp -> link != NULL )
   temp = temp -> link ;
  /* add node at the end */
  r = ( struct node * ) malloc ( sizeof ( struct node ) ) ;
  r -> data = num ;
  r -> link = NULL ;
  temp -> link = r ;
 }
}
/* adds a new node at the beginning of the linked list */
void addatbeg ( struct node **q, int num )
{
 struct node *temp ;
 /* add new node */
 temp = ( struct node * ) malloc ( sizeof ( struct node ) ) ;
 temp -> data = num ;
 temp -> link = *q ;
 *q = temp ;
}
/* adds a new node after the specified number of nodes */
void addafter ( struct node *q, int loc, int num )
{
 struct node *temp, *r ;
 int i ;
 temp = q ;
 /* skip to desired portion */
 for ( i = 0 ; i < loc ; i++ )
 {
  temp = temp -> link ;
  /* if end of linked list is encountered */
  if ( temp == NULL )
  {
   printf ( "There are less than %d elements in list\n", loc ) ;
   return ;
  }
 }
 /* insert new node */
 r = ( struct node * ) malloc ( sizeof ( struct node ) ) ;
 r -> data = num ;
 r -> link = temp -> link ;
 temp -> link = r ;
}
/* displays the contents of the linked list */
void display ( struct node *q )
{
 /* traverse the entire linked list */
 while ( q != NULL )
 {
  printf ( "%d ", q -> data ) ;
  q = q -> link ;
 }
 printf ( "\n" ) ;
}
/* counts the number of nodes present in the linked list */
int count ( struct node * q )
{
 int c = 0 ;
 /* traverse the entire linked list */
 while ( q != NULL )
 {
  q = q -> link ;
  c++ ;
 }
 return c ;
}
/* deletes the specified node from the linked list */
void del ( struct node **q, int num )
{
 struct node *old, *temp ;
 temp = *q ;
 while ( temp != NULL )
 {
  if ( temp -> data == num )
  {
   /* if node to be deleted is the first node in the linked list */
   if ( temp == *q )
    *q = temp -> link ;
   /* deletes the intermediate nodes in the linked list */
   else
    old -> link = temp -> link ;
   /* free the memory occupied by the node */
   free ( temp ) ;
   return ;
  }
  /* traverse the linked list till the last node is reached */
  else
  {
   old = temp ;  /* old points to the previous node */
   temp = temp -> link ;  /* go to the next node */
   }
 }
 printf ( "Element %d not found\n", num ) ;
}