doubly linked list

Author: accodes21

doublyLinkedList.cpp

@@ -0,0 +1,147 @@
+#include <iostream>
+using namespace std;
+
+class Node{
+    public:
+    int data;
+    Node* prev;
+    Node* next;
+
+    Node(int d){
+        this ->data = d;
+        this ->next = NULL;
+        this ->prev = NULL;
+    }
+
+    ~Node() {
+        int val = this -> data;
+        if(next != NULL) {
+            delete next;
+            next = NULL;
+        }
+        cout << "memory free for node with data "<< val << endl;
+    }
+};
+
+void print(Node* &head){
+    Node* temp = head;
+
+    while(temp != NULL){
+        cout<< temp ->data << " ";
+        temp = temp ->next;
+    }
+    cout << endl;
+}
+
+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){
+    //empty list
+    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 insertNode(Node* &tail, Node* &head, int pos, int d){
+    //insert start
+    if(pos==1){
+        insertAtHead(tail, head, d);
+        return ;
+    }
+
+    Node* temp = head;
+    int c = 1;
+    while(c < pos-1){
+        temp = temp ->next;
+        c++;
+    }
+
+    //insert at end
+    if(temp -> next == NULL){
+        insertAtTail(tail, head, d);
+        return ;
+    }
+
+    //creating a new node
+    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* node1 = new Node(10);
+    Node* head  = NULL;
+    Node* tail  = NULL;
+    
+    insertNode(tail, head, 1, 1);
+    print(head);
+
+    insertAtHead(tail, head, 12);
+    print(head);
+
+    insertAtTail(tail, head, 15);
+    print(head);
+
+    insertNode(tail, head, 2, 30);
+    print(head);
+
+    insertNode(tail, head, 1, 10);
+    print(head);
+
+    return 0;
+}