Added DoublyLinkedList

C Programming Language/Linked Lists/Doubly Linked lists/doublyll.cpp

@@ -0,0 +1,261 @@
+//Program for performing operations on doubly linked list
+
+#include<iostream>
+#include<string.h>
+using namespace std;
+
+class node
+{
+friend class list;
+int data;
+node *prev;
+node *next;
+
+public:
+node(int d)
+{
+    prev=NULL;
+	data=d;
+	next=NULL;
+}
+
+};
+
+class list
+{
+	node *head;
+
+public:
+	list()
+	{
+		head=NULL;
+	}
+	void createmember()
+	{
+		int data;
+		char choice;
+		node *temp,*ptr;
+
+        do
+        {
+
+            cout<<"Enter data: ";
+            cin>>data;
+
+            temp= new node(data);
+
+			if(head==NULL)
+			{
+				head=temp;
+			}
+			else
+			{
+				ptr=head;
+				while(ptr->next!=NULL)
+				{
+					ptr=ptr->next;
+				}
+				temp->prev=ptr;
+				ptr->next=temp;
+			}
+			cout<<"Node is inserted!"<<endl;
+            cout<<"\nDo you want to continue the process, yes(y) ? ";
+            cin>>choice;
+        }while(choice=='y'||choice=='Y');
+
+	}
+
+	void display()
+	{
+
+		node *ptr;
+
+		if(head==NULL)
+		{
+			cout<<"List is empty!"<<endl;
+		}
+		else
+		{
+			ptr=head;
+
+			while(ptr!=NULL)
+			{
+				cout<<ptr->data<<"\t";
+				ptr=ptr->next;
+			}
+			cout<<endl;
+		}
+	}
+
+
+	void merge(list l1,list l2)
+	{
+	   node *ptr1,*ptr2,*ptr;
+
+	ptr1=l1.head;
+	ptr2=l2.head;
+	ptr=head;
+
+	while((ptr1!=NULL) && (ptr2!=NULL))
+	{
+		if(ptr1->data > ptr2->data)
+		{
+			if(head==NULL)
+			{
+				head=ptr1;
+				ptr=ptr1;
+			}
+			else
+			{
+				ptr1->prev=ptr;
+				ptr->next=ptr1;
+				ptr=ptr->next;
+			}
+			ptr1=ptr1->next;
+		}
+        else if(ptr1->data < ptr2->data)
+		{
+			if(head==NULL)
+			{
+				head=ptr2;
+				ptr=ptr2;
+			}
+			else
+			{
+				ptr2->prev=ptr;
+				ptr->next=ptr2;
+				ptr=ptr->next;
+			}
+			ptr2=ptr2->next;
+		}
+
+	}
+    if(ptr1!=NULL)
+	{
+	    ptr1->prev=ptr;
+		ptr->next=ptr1;
+	}
+	if(ptr2!=NULL)
+	{
+	    ptr2->prev=ptr;
+        ptr->next=ptr2;
+
+    }
+
+	display();
+
+	}
+
+
+};
+
+int main() {
+
+	list l1,l2,l3;
+	int ch;
+
+	cout<<"\n...LIST1..."<<endl;
+    l1.createmember();
+    cout<<"\n...LIST2..."<<endl;
+	l2.createmember();
+
+	cout<<"----MENU----"<<endl;
+	cout<<"1.Display"<<endl;
+	cout<<"2.Merge"<<endl;
+	cout<<"3.Exit"<<endl;
+	cout<<"------------"<<endl;
+
+
+	while(1)
+	{
+		cout<<"\n\nEnter your choice: ";
+		cin>>ch;
+		switch(ch)
+		{
+			case 1:
+                    cout<<"\n...LIST1..."<<endl;
+					l1.display();
+					cout<<"\n...LIST2..."<<endl;
+					l2.display();
+					break;
+
+			case 2:
+                    l3.merge(l1,l2);
+                    break;
+
+            case 3:
+                    cout<<"Program closed!"<<endl;
+                    //exit(1);
+                    break;
+
+			default:
+					cout<<"Invalid choice"<<endl;
+                    break;
+		}
+	}
+	return 0;
+}
+
+
+/*
+
+OUTPUT:
+
+
+...LIST1...
+Enter data: 7
+Node is inserted!
+
+Do you want to continue the process, yes(y) ? y
+Enter data: 5
+Node is inserted!
+
+Do you want to continue the process, yes(y) ? y
+Enter data: 3
+Node is inserted!
+
+Do you want to continue the process, yes(y) ? y
+Enter data: 1
+Node is inserted!
+
+Do you want to continue the process, yes(y) ? n
+
+...LIST2...
+Enter data: 6
+Node is inserted!
+
+Do you want to continue the process, yes(y) ? y
+Enter data: 4
+Node is inserted!
+
+Do you want to continue the process, yes(y) ? y
+Enter data: 2
+Node is inserted!
+
+Do you want to continue the process, yes(y) ? n
+----MENU----
+1.Display
+2.Merge
+3.Exit
+------------
+
+
+Enter your choice: 1
+
+...LIST1...
+7       5       3       1
+
+...LIST2...
+6       4       2
+
+
+Enter your choice: 2
+7       6       5       4       3       2       1
+
+
+Enter your choice: 3
+Program closed!
+
+
+
+*/