reverse.cpp file added

Author: kiruba-r11

Data Structures/Linked Lists/Circular Doubly Linked Lists/reverse.cpp

@@ -0,0 +1,117 @@
+/*
+
+This is a Circular Doubly Linked List program which deletes a Node at the end of the Linked Lists.
+Since, it is a Ciruclar Doubly Linked List, both the forward and backward traversal is also possible.
+
+*/
+
+#include <iostream>
+
+using namespace std;
+
+/*
+
+Node definition:
+1. Pointer to previous node.
+2. Integer Data
+3. Pointer to next node.
+
+*/
+
+class dcll_node {
+public:
+dcll_node* prev;
+int data;
+dcll_node* next;
+};
+
+void createDCLL(dcll_node* &head) {
+
+dcll_node* temp = head;
+
+int choice;
+
+do {
+
+int data;
+
+cout << "Enter Data : ";
+cin >> data;
+
+dcll_node* newNode = new dcll_node();
+newNode->data = data;
+newNode->prev = NULL;
+newNode->next = NULL;
+
+if(head == NULL) {
+head = newNode;
+temp = head;
+head->next = head;
+head->prev = head;
+} else {
+temp->next = newNode;
+newNode->prev = temp;
+temp = newNode;
+newNode->next = head;
+head->prev = newNode;
+}
+
+cout << "Do you want to continue? (1/0) : ";
+cin >> choice;
+
+} while(choice == 1);
+
+}
+
+void reverse(dcll_node* &head) {
+
+if(head == NULL || head->next == head)
+return;
+
+head->prev->next = NULL;
+
+dcll_node *p = NULL , *q = head , *r = head->next;
+while(r != NULL) {
+q->next = p;
+q->prev = r;
+p = q;
+q = r;
+r = r->next;
+}
+
+q->next = p;
+q->prev = head;
+head->next = q;
+head = q;
+}
+
+void display(dcll_node* head) {
+
+dcll_node* temp = head;
+
+cout << "The elements are : ";
+do {
+
+cout << temp->data << " ";
+temp = temp->next;
+
+} while(temp != head);
+
+cout << endl;
+}
+
+int main() {
+
+dcll_node* head = NULL;
+createDCLL(head);
+
+cout << "Before Reversing : " << endl;
+display(head);
+
+reverse(head);
+
+cout << "After Reversing : " << endl;
+display(head);
+
+return 0;
+}