Swap Nodes in a Doubly Linked List

C++ Programming Language/Stack/Swap Nodes in Doubly Linked List.cpp

@@ -0,0 +1,108 @@
+#include<iostream>
+#include<cmath>
+using namespace std ;
+class Node {
+    public:
+    int data;
+    struct Node* next; // Pointer to next node in DLL
+    struct Node* prev; // Pointer to previous node in DLL
+    Node(int data)
+    {
+        this->data = data ;
+        next = NULL ;
+        prev = NULL ;
+    }
+};
+void print(Node* head)
+{
+    Node* temp = head ;
+    cout<<temp->data<<" ";
+    temp = temp->next ;
+    while(temp != head)
+    {
+        cout<<temp->data<<" ";
+        temp = temp->next ;
+    }
+}
+Node* Swap_Nodes(Node* head , int i , int j)
+{
+    if(head == NULL)
+        return NULL ;
+    Node* a = head ;
+    Node* b = head ;
+    for(int k=0;k<i;k++)
+    {
+        a = a->next ;
+    }
+    for(int k=0;k<j;k++)
+    {
+        b = b->next ;
+    }
+    if(i==j)
+        return head ;
+
+
+    if(abs(i-j) == 1)
+    {
+        Node* z = a->prev ;
+        a->prev->next = b ;
+        a->next = b->next ;
+        a->prev = b ;
+        b->next = a ;
+        a->next->prev = a ;
+        b->prev = z ;
+    }
+
+    else{
+
+
+
+    Node* x = a->prev ;
+    Node* y = a->next ;
+    a->prev->next = b ;
+    a->next->prev = b ;
+    a->prev = b->prev ;
+    a->next = b->next ;
+    b->prev->next = a ;
+    b->next->prev = a ;
+    b->prev = x ;
+    b->next = y ;
+    }
+    if(i==0)
+       head = b ;
+    if(j==0)
+       head = a ;
+    return head ;
+}
+int main()
+{
+    Node *a = new Node(1);
+    Node *b = new Node(2);
+    Node *c = new Node(3);
+    Node *d = new Node(4);
+    Node *e = new Node(5);
+    Node *f = new Node(6);
+    a->next = b ;
+    b->next = c ;
+    c->next = d ;
+    d->next = e ;
+    e->next = f ;
+    f->next = a ;
+    a->prev = f ;
+    b->prev = a ;
+    c->prev = b ;
+    d->prev = c ;
+    e->prev = d ;
+    f->prev = e ;
+    cout<<"Original List : ";
+    print(a) ;
+    cout<<endl ;
+    int x,y;
+    cout<<"Enter positions at which you want the Nodes to be Swapped (positon < 6): ";
+    cin>>x>>y;
+    a = Swap_Nodes(a,x,y);
+    cout<<"List After Swapping at Position "<<x<<" and "<<y<<" is : ";
+    print(a);
+    cout<<endl ;
+    return 0 ;
+}