C program to find the length of linked list

Linked lists use dynamic memory allocation i.e. they grow and shrink accordingly. They are defined as a collection of nodes. Here, nodes have two parts, which are data and link. The representation of data, link and linked lists is given below −

Types of Linked Lists

Linked lists have four types, which are as follows −

• Single / Singly linked lists
• Double / Doubly linked lists
• Circular single linked list
• Circular double linked list

The logic we used to find the length of linked list by using recursion method is −

int length(node *temp){
   if(temp==NULL)
      return l;
   else{
      l=l+1;
      length(temp->next);
   }
}

Program

Following is the C program to find the length of linked list −

 Live Demo

#include <stdio.h>
#include <stdlib.h>
typedef struct linklist{
   int data;
   struct linklist *next;
}node;
int l=0;
int main(){
   node *head=NULL,*temp,*temp1;
   int len,choice,count=0,key;
   do{
      temp=(node *)malloc(sizeof(node));
      if(temp!=NULL){
         printf("
enter the elements in a list : ");
         scanf("%d",&temp->data);
         temp->next=NULL;
         if(head==NULL){
            head=temp;
         }else{
            temp1=head;
            while(temp1->next!=NULL){
               temp1=temp1->next;
            }
            temp1->next=temp;
         }
      }else{
         printf("
Memory is full");
      }
      printf("
press 1 to enter data into list: ");
      scanf("%d",&choice);
   }while(choice==1);
   len=length(head);
   printf("The list has %d no of nodes",l);
   return 0;
}
//recursive function to find length
int length(node *temp){
   if(temp==NULL)
      return l;
   else{
      l=l+1;
      length(temp->next);
   }
}

Output

When the above program is executed, it produces the following result −

Run 1:
enter the elements in a list: 3
press 1 to enter data into list: 1
enter the elements in a list: 56
press 1 to enter data into list: 1
enter the elements in a list: 56
press 1 to enter data into list: 0
The list has 3 no of nodes
Run 2:
enter the elements in a list: 12
press 1 to enter data into list: 1
enter the elements in a list: 45
press 1 to enter data into list: 0
The list has 2 no of nodes