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× Data Structures - Circular Singly Linked List Other Related Topics


In this method, a new node is inserted at the end of the circular singly linked list. For example - if the given List is 10->20->30 and a new element 100 is added at the end, the List becomes 10->20->30->100.

Inserting a new node at the end of the circular singly linked list is very easy. First, a new node with given element is created. It is then added at the end of the list by linking the last node and head node to the new node.

Circular Singly Linked List - Add Node At End

The function push_back is created for this purpose. It is a 6-step process.

void push_back(int newElement) {
  
  //1. allocate node
  Node* newNode = new Node();
  
  //2. assign data element
  newNode->data = newElement;
  
  //3. assign null to the next of new node
  newNode->next = NULL; 
  
  //4. Check the list is empty or not,
  //   if empty make the new node as head 
  if(head == NULL) {
    head = newNode;
    newNode->next = head;
  } else {
    
    //5. Else, traverse to the last node
    Node* temp = head;
    while(temp->next != head)
      temp = temp->next;
    
    //6. Adjust the links
    temp->next = newNode;
    newNode->next = head;
  }    
}
void push_back(struct Node** head_ref, int newElement) {  
  
  //1. allocate node
  struct Node *newNode, *temp;
  newNode = (struct Node*)malloc(sizeof(struct Node)); 
  
  //2. assign data element
  newNode->data = newElement;  
  
  //3. assign null to the next of new node
  newNode->next = NULL;
  
  //4. Check the list is empty or not,
  //   if empty make the new node as head 
  if(*head_ref == NULL) {
    *head_ref = newNode;
    newNode->next = *head_ref;
  } else {
    
    //5. Else, traverse to the last node
    temp = *head_ref;
    while(temp->next != *head_ref) {
      temp = temp->next;
    }    
    
    //6. Adjust the links
    temp->next = newNode;
    newNode->next = *head_ref;
  }
}
def push_back(self, newElement):
  
  #1 & 2 & 3. allocate node, assign data element
  #          assign null to the next of new node
  newNode = Node(newElement)
  
  #4. Check the list is empty or not,
  #   if empty make the new node as head 
  if(self.head == None):
    self.head = newNode
    newNode.next = self.head
    return
  else:
    
    #5. Else, traverse to the last node
    temp = self.head
    while(temp.next != self.head):
      temp = temp.next
    
    #6. Adjust the links  
    temp.next = newNode
    newNode.next = self.head
void push_back(int newElement) {
  
  //1. allocate node
  Node newNode = new Node();
  
  //2. assign data element
  newNode.data = newElement;
  
  //3. assign null to the next of new node
  newNode.next = null; 
  
  //4. Check the list is empty or not,
  //   if empty make the new node as head 
  if(head == null) {
    head = newNode;
    newNode.next = head;
  } else {
    
    //5. Else, traverse to the last node
    Node temp = new Node();
    temp = head;
    while(temp.next != head)
      temp = temp.next;
    
    //6. Adjust the links
    temp.next = newNode;
    newNode.next = head;
  }    
}
public void push_back(int newElement) {
  
  //1. allocate node
  Node newNode = new Node();
  
  //2. assign data element
  newNode.data = newElement;
  
  //3. assign null to the next of new node
  newNode.next = null; 
  
  //4. Check the list is empty or not,
  //   if empty make the new node as head
  if(head == null) {
    head = newNode;
    newNode.next = head;
  } else {
    
    //5. Else, traverse to the last node
    Node temp = new Node();
    temp = head;
    while(temp.next != head)
      temp = temp.next;
    
    //6. Adjust the links
    temp.next = newNode;
    newNode.next = head;
  }    
}
public function push_back($newElement) {
  
  //1. allocate node
  $newNode = new Node();
  
  //2. assign data element
  $newNode->data = $newElement;
  
  //3. assign null to the next of new node
  $newNode->next = null; 
  
  //4. Check the list is empty or not,
  //   if empty make the new node as head 
  if($this->head == null) {
    $this->head = $newNode;
    $newNode->next = $this->head;
  } else {
    
    //5. Else, traverse to the last node
    $temp = new Node();
    $temp = $this->head;
    while($temp->next !== $this->head) {
      $temp = $temp->next;
    }
    
    //6. Adjust the links
    $temp->next = $newNode;
    $newNode->next = $this->head;
  }    
}

The below is a complete program that uses above discussed concept to insert new node at the end of the circular singly linked list.

#include <iostream>
using namespace std;

//node structure
struct Node {
    int data;
    Node* next;
};

class LinkedList {
  private:
    Node* head;
  public:
    LinkedList(){
      head = NULL;
    }
 
    //Add new element at the end of the list
    void push_back(int newElement) {
      Node* newNode = new Node();
      newNode->data = newElement;
      newNode->next = NULL; 
      if(head == NULL) {
        head = newNode;
        newNode->next = head;
      } else {
        Node* temp = head;
        while(temp->next != head)
          temp = temp->next;
        temp->next = newNode;
        newNode->next = head;
      }    
    }

    //display the content of the list
    void PrintList() {
      Node* temp = head;
      if(temp != NULL) {
        cout<<"\nThe list contains: ";
        while(true) {
          cout<<temp->data<<" ";
          temp = temp->next;
          if(temp == head) 
            break;
        }
      } else {
        cout<<"\nThe list is empty.";
      }
    }     
};

// test the code 
int main() {
  LinkedList MyList;

  //Add three elements at the end of the list.
  MyList.push_back(10);
  MyList.push_back(20);
  MyList.push_back(30);
  MyList.PrintList();
  
  return 0; 
}

The above code will give the following output:

The list contains: 10 20 30 
#include <stdio.h>
#include <stdlib.h>

//node structure
struct Node {
  int data;
  struct Node* next;
};

//Add new element at the end of the list
void push_back(struct Node** head_ref, int newElement) {  
  struct Node *newNode, *temp;
  newNode = (struct Node*)malloc(sizeof(struct Node)); 
  newNode->data = newElement;  
  newNode->next = NULL;
  if(*head_ref == NULL) {
    *head_ref = newNode;
     newNode->next = *head_ref;
  } else {
    temp = *head_ref;
    while(temp->next != *head_ref) {
      temp = temp->next;
    }    
    temp->next = newNode;
    newNode->next = *head_ref;
  }
}

//display the content of the list
void PrintList(struct Node* head_ref) {
  struct Node* temp = head_ref;
  if(head_ref != NULL) {
    printf("\nThe list contains: ");
    while (1) {
      printf("%i ",temp->data);
      temp = temp->next;
      if(temp == head_ref)
        break;    
    }
  } else {
    printf("\nThe list is empty.");
  }   
}

// test the code 
int main() {
  struct Node* MyList = NULL;

  //Add three elements at the end of the list.
  push_back(&MyList, 10);
  push_back(&MyList, 20);
  push_back(&MyList, 30);
  PrintList(MyList);

  return 0; 
}

The above code will give the following output:

The list contains: 10 20 30 
# node structure
class Node:
  def __init__(self, data):
    self.data = data
    self.next = None

#class Linked List
class LinkedList:
  def __init__(self):
    self.head = None

  #Add new element at the end of the list
  def push_back(self, newElement):
    newNode = Node(newElement)
    if(self.head == None):
      self.head = newNode
      newNode.next = self.head
      return
    else:
      temp = self.head
      while(temp.next != self.head):
        temp = temp.next
      temp.next = newNode
      newNode.next = self.head

  #display the content of the list
  def PrintList(self):
    temp = self.head
    if(temp != None):
      print("\nThe list contains:", end=" ")
      while (True):
        print(temp.data, end=" ")
        temp = temp.next
        if(temp == self.head):
          break
    else:
      print("\nThe list is empty.")

# test the code                  
MyList = LinkedList()

#Add three elements at the end of the list.
MyList.push_back(10)
MyList.push_back(20)
MyList.push_back(30)
MyList.PrintList()

The above code will give the following output:

The list contains: 10 20 30 
//node structure
class Node {
    int data;
    Node next;
};

class LinkedList {
  Node head;

  LinkedList(){
    head = null;
  }

  //Add new element at the end of the list
  void push_back(int newElement) {
    Node newNode = new Node();
    newNode.data = newElement;
    newNode.next = null; 
    if(head == null) {
      head = newNode;
      newNode.next = head;
    } else {
      Node temp = new Node();
      temp = head;
      while(temp.next != head)
        temp = temp.next;
      temp.next = newNode;
      newNode.next = head;
    }    
  }

  //display the content of the list
  void PrintList() {
    Node temp = new Node();
    temp = this.head;
    if(temp != null) {
      System.out.print("\nThe list contains: ");
      while(true) {
        System.out.print(temp.data + " ");
        temp = temp.next;
        if(temp == this.head)
          break;
      }
    } else {
      System.out.print("\nThe list is empty.");
    }
  }     
};

// test the code 
public class Implementation {
  public static void main(String[] args) {
    LinkedList MyList = new LinkedList();

    //Add three elements at the end of the list.
    MyList.push_back(10);
    MyList.push_back(20);
    MyList.push_back(30);
    MyList.PrintList(); 
  }
}

The above code will give the following output:

The list contains: 10 20 30 
using System;

//node structure
class Node {
  public int data;
  public Node next;
};

class LinkedList {
  Node head;

  public LinkedList(){
    head = null;
  }
  
  //Add new element at the end of the list
  public void push_back(int newElement) {
    Node newNode = new Node();
    newNode.data = newElement;
    newNode.next = null; 
    if(head == null) {
      head = newNode;
      newNode.next = head;
    } else {
      Node temp = new Node();
      temp = head;
      while(temp.next != head)
        temp = temp.next;
      temp.next = newNode;
      newNode.next = head;
    }    
  }

  //display the content of the list
  public void PrintList() {
    Node temp = new Node();
    temp = this.head;
    if(temp != null) {
      Console.Write("\nThe list contains: ");
      while(true) {
        Console.Write(temp.data + " ");
        temp = temp.next;
        if(temp == this.head)
          break;        
      }
    } else {
      Console.Write("\nThe list is empty.");
    }
  }      
};

// test the code
class Implementation {  
  static void Main(string[] args) {
    LinkedList MyList = new LinkedList();

    //Add three elements at the end of the list.
    MyList.push_back(10);
    MyList.push_back(20);
    MyList.push_back(30);
    MyList.PrintList();   
  }
}

The above code will give the following output:

The list contains: 10 20 30 
<?php
//node structure
class Node {
  public $data;
  public $next;
}

class LinkedList {
  public $head;

  public function __construct(){
    $this->head = null;
  }
  
  //Add new element at the end of the list
  public function push_back($newElement) {
    $newNode = new Node();
    $newNode->data = $newElement;
    $newNode->next = null; 
    if($this->head == null) {
      $this->head = $newNode;
      $newNode->next = $this->head;
    } else {
      $temp = new Node();
      $temp = $this->head;
      while($temp->next !== $this->head) {
        $temp = $temp->next;
      }
      $temp->next = $newNode;
      $newNode->next = $this->head;
    }    
  }

  //display the content of the list
  public function PrintList() {
    $temp = new Node();
    $temp = $this->head;
    if($temp != null) {
      echo "\nThe list contains: ";
      while(true) {
        echo $temp->data." ";
        $temp = $temp->next;
        if($temp == $this->head)
          break;        
      }
    } else {
      echo "\nThe list is empty.";
    }
  }    
};

// test the code  
$MyList = new LinkedList();

//Add three elements at the end of the list.
$MyList->push_back(10);
$MyList->push_back(20);
$MyList->push_back(30);
$MyList->PrintList();
?>

The above code will give the following output:

The list contains: 10 20 30