Create Doubly LinkedList.cpp

C++/Linked List/Doubly LinkedList.cpp

@@ -0,0 +1,203 @@
+#include<iostream>
+using namespace std;
+
+class Node {
+    public:
+    int data;
+    Node* prev;
+    Node* next;
+
+    //constructor
+    Node(int d ) {
+        this-> data = d;
+        this->prev = NULL;
+        this->next = NULL;
+    }
+
+    ~Node() {
+        int val = this -> data;
+        if(next != NULL) {
+            delete next;
+            next = NULL;
+        }
+        cout << "memory free for node with data "<< val << endl;
+    }
+};
+
+//traversing a linked list
+void print(Node* head) {
+    Node* temp  = head ;
+
+    while(temp != NULL) {
+        cout << temp -> data << " ";
+        temp  = temp -> next;
+    }
+    cout << endl;
+}
+
+//gives length of Linked List
+int getLength(Node* head) {
+    int len = 0;
+    Node* temp  = head ;
+
+    while(temp != NULL) {
+        len++;
+        temp  = temp -> next;
+    }
+
+    return len;
+}
+void insertAtHead(Node* &tail, Node* &head, int d) {
+
+    //empty list
+    if(head == NULL) {
+        Node* temp = new Node(d);
+        head = temp;
+        tail = temp;
+    }
+    else{
+        Node* temp = new Node(d);
+        temp -> next = head;
+        head -> prev = temp;
+        head = temp;
+    }
+
+}
+
+
+void insertAtTail(Node* &tail,Node* &head, int d) {
+    if(tail == NULL) {
+        Node* temp = new Node(d);
+        tail = temp;
+        head = temp;
+    }
+    else{
+        Node* temp = new Node(d);
+        tail -> next  = temp;
+        temp -> prev = tail;
+        tail = temp;
+    }
+
+}
+
+void insertAtPosition(Node* & tail, Node* &head, int position, int d) {
+
+    //insert at Start
+    if(position == 1) {
+        insertAtHead(tail,head, d);
+        return;
+    }
+
+    Node* temp  = head;
+    int cnt = 1;
+
+    while(cnt < position-1) {
+        temp = temp->next;
+        cnt++;
+    }
+
+    //inserting at Last Position
+    if(temp -> next == NULL) {
+        insertAtTail(tail,head,d);
+        return ;
+    }
+
+    //creating a node for d
+    Node* nodeToInsert = new Node(d);
+
+    nodeToInsert ->next = temp -> next;
+    temp -> next -> prev = nodeToInsert;
+    temp -> next = nodeToInsert;
+    nodeToInsert -> prev = temp;
+}
+
+void deleteNode(int position, Node* & head) { 
+
+    //deleting first or start node
+    if(position == 1) {
+        Node* temp = head;
+        temp -> next -> prev = NULL;
+        head = temp ->next;
+        temp -> next = NULL;
+        delete temp;
+    }
+    else
+    {
+        //deleting any middle node or last node
+        Node* curr = head;
+        Node* prev = NULL;
+
+        int cnt = 1;
+        while(cnt < position) {
+            prev = curr;
+            curr = curr -> next;
+            cnt++;
+        }
+
+        curr -> prev = NULL;
+        prev -> next = curr -> next;
+        curr -> next = NULL;
+
+        delete curr;
+
+    }
+}
+
+
+
+int main() {
+
+
+    Node* head = NULL;
+    Node* tail = NULL;
+
+    print(head);
+    //cout << getLength(head) << endl;
+
+    insertAtHead(tail,head, 11);
+    print(head);
+    cout << "head  " << head -> data << endl;
+    cout << "tail  " << tail -> data << endl;
+
+    insertAtHead(tail,head, 13);
+    print(head);
+    cout << "head  " << head -> data << endl;
+    cout << "tail  " << tail -> data << endl;
+
+    insertAtHead(tail,head, 8);
+    print(head);
+    cout << "head  " << head -> data << endl;
+    cout << "tail  " << tail -> data << endl;
+
+    insertAtTail(tail,head, 25);
+    print(head);
+    cout << "head  " << head -> data << endl;
+    cout << "tail  " << tail -> data << endl;
+
+    insertAtPosition(tail, head, 2, 100);
+    print(head);
+    cout << "head  " << head -> data << endl;
+    cout << "tail  " << tail -> data << endl;
+
+    insertAtPosition(tail, head, 1, 101);
+    print(head);
+
+    cout << "head  " << head -> data << endl;
+    cout << "tail  " << tail -> data << endl;
+
+    insertAtPosition(tail, head, 7, 102);
+    print(head);
+    cout << "head  " << head -> data << endl;
+    cout << "tail  " << tail -> data << endl;
+
+    deleteNode(7, head);
+    print(head);
+    cout << "head  " << head -> data << endl;
+    cout << "tail  " << tail -> data << endl;
+
+
+
+
+
+    return 0;
+}