Circular Doubly Linked List - Search an element
Searching an element in a circular doubly linked list requires creating a temp node pointing to the head of the list. Along with this, two more variables are required to track search and track index of the current node. If the temp node is not null at the start, then traverse th list to check if current node value matches with the search value. If it matches then update search tracker variable and stop traversing the list, else keep on traversing the list. If the temp node is empty at the start, then the list contains no item.
The function SearchElement is created for this purpose. It is a 4-step process.
void SearchElement(int searchValue) { //1. create a temp node pointing to head Node* temp = head; //2. create two variables: found - to track // search, idx - to track current index int found = 0; int i = 0; //3. if the temp node is not null check the // node value with searchValue, if found // update variables and break the loop, else // continue searching till temp node is not head if(temp != NULL) { while(true) { i++; if(temp->data == searchValue) { found++; break; } temp = temp->next; if(temp == head) {break;} } if (found == 1) { cout<<searchValue<<" is found at index = "<<i<<".\n"; } else { cout<<searchValue<<" is not found in the list.\n"; } } else { //4. If the temp node is null at the start, // the list is empty cout<<"The list is empty.\n"; } }
void SearchElement(struct Node* head_ref, int searchValue) { //1. create a temp node pointing to head struct Node* temp = head_ref; //2. create two variables: found - to track // search, idx - to track current index int found = 0; int i = 0; //3. if the temp node is not null check the // node value with searchValue, if found // update variables and break the loop, else // continue searching till temp node is not head if(temp != NULL) { while(1) { i++; if(temp->data == searchValue) { found++; break; } temp = temp->next; if(temp == head_ref) {break;} } if (found == 1) { printf("%i is found at index = %i.\n", searchValue, i); } else { printf("%i is not found in the list.\n", searchValue); } } else { //4. If the temp node is null at the start, // the list is empty printf("The list is empty.\n"); } }
def SearchElement(self, searchValue): #1. create a temp node pointing to head temp = self.head #2. create two variables: found - to track # search, idx - to track current index found = 0 i = 0 #3. if the temp node is not null check the # node value with searchValue, if found # update variables and break the loop, else # continue searching till temp node is not head if(temp != None): while (True): i += 1 if(temp.data == searchValue): found += 1 break temp = temp.next if(temp == self.head): break if(found == 1): print(searchValue,"is found at index =", i) else: print(searchValue,"is not found in the list.") else: #4. If the temp node is null at the start, # the list is empty print("The list is empty.")
void SearchElement(int searchValue) { //1. create a temp node pointing to head Node temp = new Node(); temp = this.head; //2. create two variables: found - to track // search, idx - to track current index int found = 0; int i = 0; //3. if the temp node is not null check the // node value with searchValue, if found // update variables and break the loop, else // continue searching till temp node is not head if(temp != null) { while(true) { i++; if(temp.data == searchValue) { found++; break; } temp = temp.next; if(temp == this.head) {break;} } if (found == 1) { System.out.println(searchValue + " is found at index = " + i +"."); } else { System.out.println(searchValue + " is not found in the list."); } } else { //4. If the temp node is null at the start, // the list is empty System.out.println("The list is empty."); } }
public void SearchElement(int searchValue) { //1. create a temp node pointing to head Node temp = new Node(); temp = this.head; //2. create two variables: found - to track // search, idx - to track current index int found = 0; int i = 0; //3. if the temp node is not null check the // node value with searchValue, if found // update variables and break the loop, else // continue searching till temp node is not head if(temp != null) { while(true) { i++; if(temp.data == searchValue) { found++; break; } temp = temp.next; if(temp == this.head) {break;} } if (found == 1) { Console.WriteLine(searchValue + " is found at index = " + i +"."); } else { Console.WriteLine(searchValue + " is not found in the list."); } } else { //4. If the temp node is null at the start, // the list is empty Console.WriteLine("The list is empty."); } }
public function SearchElement($searchValue) { //1. create a temp node pointing to head $temp = new Node(); $temp = $this->head; //2. create two variables: found - to track // search, idx - to track current index $found = 0; $i = 0; //3. if the temp node is not null check the // node value with searchValue, if found // update variables and break the loop, else // continue searching till temp node is not head if($temp != null) { while(true) { $i++; if($temp->data == $searchValue) { $found++; break; } $temp = $temp->next; if($temp == $this->head) {break;} } if ($found == 1) { echo $searchValue." is found at index = ".$i.".\n"; } else { echo $searchValue." is not found in the list.\n"; } } else { //4. If the temp node is null at the start, // the list is empty echo "The list is empty.\n"; } }
The below is a complete program that uses above discussed concept to search an element in a given circular doubly linked list.
#include <iostream> using namespace std; //node structure struct Node { int data; Node* next; Node* prev; }; 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; newNode->prev = NULL; if(head == NULL) { head = newNode; newNode->next = head; newNode->prev = head; } else { Node* temp = head; while(temp->next != head) temp = temp->next; temp->next = newNode; newNode->next = head; newNode->prev = temp; head->prev = newNode; } } //Search an element in the list void SearchElement(int searchValue) { Node* temp = head; int found = 0; int i = 0; if(temp != NULL) { while(true) { i++; if(temp->data == searchValue) { found++; break; } temp = temp->next; if(temp == head) {break;} } if (found == 1) { cout<<searchValue<<" is found at index = "<<i<<".\n"; } else { cout<<searchValue<<" is not found in the list.\n"; } } else { cout<<"The list is empty.\n"; } } //display the content of the list void PrintList() { Node* temp = head; if(temp != NULL) { cout<<"The list contains: "; while(true) { cout<<temp->data<<" "; temp = temp->next; if(temp == head) break; } cout<<endl; } else { cout<<"The list is empty.\n"; } } }; // 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); //traverse to display the content of the list. MyList.PrintList(); //search for element in the list MyList.SearchElement(10); MyList.SearchElement(15); MyList.SearchElement(20); return 0; }
The above code will give the following output:
The list contains: 10 20 30 10 is found at index = 1. 15 is not found in the list. 20 is found at index = 2.
#include <stdio.h> #include <stdlib.h> //node structure struct Node { int data; struct Node* next; struct Node* prev; }; //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; newNode->prev = NULL; if(*head_ref == NULL) { *head_ref = newNode; newNode->next = *head_ref; newNode->prev = *head_ref; } else { temp = *head_ref; while(temp->next != *head_ref) { temp = temp->next; } temp->next = newNode; newNode->next = *head_ref; newNode->prev = temp; (*head_ref)->prev = newNode; } } //Search an element in the list void SearchElement(struct Node* head_ref, int searchValue) { struct Node* temp = head_ref; int found = 0; int i = 0; if(temp != NULL) { while(1) { i++; if(temp->data == searchValue) { found++; break; } temp = temp->next; if(temp == head_ref) {break;} } if (found == 1) { printf("%i is found at index = %i.\n", searchValue, i); } else { printf("%i is not found in the list.\n", searchValue); } } else { printf("The list is empty.\n"); } } //display the content of the list void PrintList(struct Node* head_ref) { struct Node* temp = head_ref; if(head_ref != NULL) { printf("The list contains: "); while (1) { printf("%i ",temp->data); temp = temp->next; if(temp == head_ref) break; } printf("\n"); } else { printf("The list is empty.\n"); } } // 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); //traverse to display the content of the list. PrintList(MyList); //search for element in the list SearchElement(MyList, 10); SearchElement(MyList, 15); SearchElement(MyList, 20); return 0; }
The above code will give the following output:
The list contains: 10 20 30 10 is found at index = 1. 15 is not found in the list. 20 is found at index = 2.
# node structure class Node: def __init__(self, data): self.data = data self.next = None self.prev = 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 newNode.prev = self.head return else: temp = self.head while(temp.next != self.head): temp = temp.next temp.next = newNode newNode.next = self.head newNode.prev = temp self.head.prev = newNode #Search an element in the list def SearchElement(self, searchValue): temp = self.head found = 0 i = 0 if(temp != None): while (True): i += 1 if(temp.data == searchValue): found += 1 break temp = temp.next if(temp == self.head): break if(found == 1): print(searchValue,"is found at index =", i) else: print(searchValue,"is not found in the list.") else: print("The list is empty.") #display the content of the list def PrintList(self): temp = self.head if(temp != None): print("The list contains:", end=" ") while (True): print(temp.data, end=" ") temp = temp.next if(temp == self.head): break print() else: print("The 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) #traverse to display the content of the list. MyList.PrintList() #search for element in the list MyList.SearchElement(10) MyList.SearchElement(15) MyList.SearchElement(20)
The above code will give the following output:
The list contains: 10 20 30 10 is found at index = 1. 15 is not found in the list. 20 is found at index = 2.
//node structure class Node { int data; Node next; Node prev; }; 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; newNode.next = null; if(head == null) { head = newNode; newNode.next = head; newNode.prev = head; } else { Node temp = new Node(); temp = head; while(temp.next != head) temp = temp.next; temp.next = newNode; newNode.next = head; newNode.prev = temp; head.prev = newNode; } } //Search an element in the list void SearchElement(int searchValue) { Node temp = new Node(); temp = this.head; int found = 0; int i = 0; if(temp != null) { while(true) { i++; if(temp.data == searchValue) { found++; break; } temp = temp.next; if(temp == this.head) {break;} } if (found == 1) { System.out.println(searchValue + " is found at index = " + i +"."); } else { System.out.println(searchValue + " is not found in the list."); } } else { System.out.println("The list is empty."); } } //display the content of the list void PrintList() { Node temp = new Node(); temp = this.head; if(temp != null) { System.out.print("The list contains: "); while(true) { System.out.print(temp.data + " "); temp = temp.next; if(temp == this.head) break; } System.out.println(); } else { System.out.println("The 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); //traverse to display the content of the list. MyList.PrintList(); //search for element in the list MyList.SearchElement(10); MyList.SearchElement(15); MyList.SearchElement(20); } }
The above code will give the following output:
The list contains: 10 20 30 10 is found at index = 1. 15 is not found in the list. 20 is found at index = 2.
using System; //node structure class Node { public int data; public Node next; public Node prev; }; 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; newNode.prev = null; if(head == null) { head = newNode; newNode.next = head; newNode.prev = head; } else { Node temp = new Node(); temp = head; while(temp.next != head) temp = temp.next; temp.next = newNode; newNode.next = head; newNode.prev = temp; head.prev = newNode; } } //Search an element in the list public void SearchElement(int searchValue) { Node temp = new Node(); temp = this.head; int found = 0; int i = 0; if(temp != null) { while(true) { i++; if(temp.data == searchValue) { found++; break; } temp = temp.next; if(temp == this.head) {break;} } if (found == 1) { Console.WriteLine(searchValue + " is found at index = " + i +"."); } else { Console.WriteLine(searchValue + " is not found in the list."); } } else { Console.WriteLine("The list is empty."); } } //display the content of the list public void PrintList() { Node temp = new Node(); temp = this.head; if(temp != null) { Console.Write("The list contains: "); while(true) { Console.Write(temp.data + " "); temp = temp.next; if(temp == this.head) break; } Console.WriteLine(); } else { Console.WriteLine("The 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); //traverse to display the content of the list. MyList.PrintList(); //search for element in the list MyList.SearchElement(10); MyList.SearchElement(15); MyList.SearchElement(20); } }
The above code will give the following output:
The list contains: 10 20 30 10 is found at index = 1. 15 is not found in the list. 20 is found at index = 2.
<?php //node structure class Node { public $data; public $next; public $prev; } 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; $newNode->prev = null; if($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; $newNode->prev = $temp; $this->head->prev = $newNode; } } //Search an element in the list public function SearchElement($searchValue) { $temp = new Node(); $temp = $this->head; $found = 0; $i = 0; if($temp != null) { while(true) { $i++; if($temp->data == $searchValue) { $found++; break; } $temp = $temp->next; if($temp == $this->head) {break;} } if ($found == 1) { echo $searchValue." is found at index = ".$i.".\n"; } else { echo $searchValue." is not found in the list.\n"; } } else { echo "The list is empty.\n"; } } //display the content of the list public function PrintList() { $temp = new Node(); $temp = $this->head; if($temp != null) { echo "The list contains: "; while(true) { echo $temp->data." "; $temp = $temp->next; if($temp == $this->head) break; } echo "\n"; } else { echo "The list is empty.\n"; } } }; // 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); //traverse to display the content of the list. $MyList->PrintList(); //search for element in the list $MyList->SearchElement(10); $MyList->SearchElement(15); $MyList->SearchElement(20); ?>
The above code will give the following output:
The list contains: 10 20 30 10 is found at index = 1. 15 is not found in the list. 20 is found at index = 2.