Find the number of nodes in the linked list using recursion

C: Program to find the number of nodes in the linked list  using recursion

#include <stdio.h>
#include <conio.h>
#include <alloc.h>

/* structure containing a data part and link part */
struct node
{
    int data ;
    struct node *link ;
} ;

void append ( struct node **, int ) ;
int length ( struct node * ) ;

void main( )
{
    struct node *p ;
    p = NULL ;  /* empty linked list */

    append ( &p, 1 ) ;
    append ( &p, 2 ) ;
    append ( &p, 3 ) ;
    append ( &p, 4 ) ;
    append ( &p, 5 ) ;

    clrscr( ) ;
    printf ( "Length of linked list = %d", length ( p ) ) ;
}

/* adds a node at the end of a linked list */
void append ( struct node **q, int num )
{
    struct node *temp ;
    temp = *q ;

    if ( *q == NULL )  /* if the list is empty, create first node */
    {
        *q = malloc ( sizeof ( struct node ) ) ;
        temp = *q ;
    }
    else
    {
        /* go to last node */
        while ( temp -> link != NULL )
            temp = temp -> link ;

        /* add node at the end */
        temp -> link = malloc ( sizeof ( struct node ) ) ;
        temp = temp -> link ;
    }

    /* assign data to the last node */
    temp -> data = num ;
    temp -> link = NULL ;
}

/* counts the number of nodes in a linked list */
int length ( struct node *q )
{
    static int l ;

    /* if list is empty or if NULL is encountered */
    if ( q == NULL )
        return ( 0 ) ;
    else
    {
        /* go to next node */
        l = 1 + length ( q -> link ) ;
        return ( l ) ;
    }
}