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



/* 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 ) ;
}
}



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