Create doublylinkedlist.java (Asiatik#120)

* Create doublylinkedlist.java

* Update doublylinkedlist.java

* Update doublylinkedlist.java

Data Structures/Linked Lists/Java/doublylinkedlist.java

@@ -0,0 +1,160 @@
+import java.io.*;
+import java.util.Scanner;
+
+//structure of linked list
+class linkedlist {
+	int data;
+	linkedlist prev;
+	linkedlist next;
+
+	linkedlist(int value) {
+		this.data = value;
+	}
+
+	void display() {
+		System.out.println(data);
+	}
+}
+
+class linked {
+	public linkedlist fstnode, lastnode;
+
+	linked() {
+		fstnode = null;
+		lastnode = null;
+	}
+
+	/* Insert node at the beginning or create linked list */
+	void insert_front(int value) {
+		linkedlist node = new linkedlist(value);
+		if(fstnode == null) {
+			node.prev = node.next = null;
+			fstnode = lastnode = node;
+			System.out.println("Lined list created successfully!");
+		}
+		else {
+			node.prev = null;
+			node.next = fstnode;
+			fstnode.prev = node;
+			fstnode = node;
+			System.out.println("Node Inserted at the front of the Linked list!");
+		}
+	}
+
+	/* Insert node at the end or create linked list */
+	void insert_end(int value) {
+		linkedlist node = new linkedlist(value);
+		if(fstnode == null) {
+			node.prev = node.next = null;
+			fstnode = lastnode = node;
+			System.out.println("Lined list created successfully!");
+		}
+		else {
+			node.next = null;
+			node.prev = lastnode;
+			lastnode.next = node;
+			lastnode = node;			
+			System.out.println("Node Inserted at the end of the Linked list!");
+		}
+	}
+
+	/* Delete node from linked list */
+	void delete() {
+		int count = 0, number, i;
+		linkedlist node, node1, node2;
+		Scanner input = new Scanner(System.in);
+
+		for(node = fstnode; node != null; node = node.next)
+			count++;
+		display();
+		node = node1 = node2 = fstnode;
+		System.out.println(count+" nodes available here!");
+		System.out.println("Enter the node number which you want to delete from ascending order list:");
+		number = Integer.parseInt(input.nextLine());
+		if(number != 1) {
+			if(number < count && number > 0) {
+				for(i = 2; i <= number; i++)
+					node = node.next;
+				for(i = 2; i <= number-1; i++)
+					node1 = node1.next;
+				for(i = 2; i <= number+1; i++)
+					node2 = node2.next;
+				node2.prev = node1;
+				node1.next = node2;
+				node.prev = null;
+				node.next = null;
+				node = null;
+			}
+			else if(number == count) {
+				node = lastnode;
+				lastnode = node.prev;
+				lastnode.next = null;
+				node = null;
+			}
+			else
+				System.out.println("Invalid node number!\n");
+		}
+		else {
+			node = fstnode;
+			fstnode = node.next;
+			fstnode.prev = null;
+			node = null;
+		}
+
+		System.out.println("Node has been deleted successfully!\n");
+	}
+
+	/* Display linked list */
+	void display() {
+		linkedlist node = fstnode;
+		System.out.println("List of node in Ascending order!");
+		while(node != null) {
+			node.display();
+			node = node.next;
+		}
+
+		node = lastnode;
+		System.out.println("List of node in Descending order!");
+		while(node != null) {
+			node.display();
+			node = node.prev;
+		}
+	}
+}
+
+//driver funtion to run the program
+class doublylinkedlist {
+	public static void main(String args[ ]) {
+		linked list = new linked();
+		Scanner input = new Scanner(System.in);
+		int op = 0;
+		while(op != 5) {
+			System.out.println("1. Insert at front 2. Insert at back 3. Delete 4. Display 5. Exit");
+			System.out.println("Enter your choice:");
+			op = Integer.parseInt(input.nextLine());
+			switch(op) {
+				case 1:
+					System.out.println("Enter the positive value for Linked list:");
+					list.insert_front(Integer.parseInt(input.nextLine()));
+					break;
+				case 2:
+					System.out.println("Enter the positive value for Linked list:");
+					list.insert_end(Integer.parseInt(input.nextLine()));
+					break;
+				case 3:
+					list.delete();
+					break;
+				case 4:
+					list.display();
+					break;
+				case 5:
+					System.out.println("Bye Bye!");
+					System.exit(0);
+					break;
+				default:
+					System.out.println("Invalid choice!");
+
+			}
+		}
+	}
+}