From b69202e16f40f78dde8eed4ff0e7af01ea18bb18 Mon Sep 17 00:00:00 2001
From: DIVYA-KUMARI1 <65301819+DIVYA-KUMARI1@users.noreply.github.com>
Date: Thu, 8 Oct 2020 20:39:05 +0530
Subject: [PATCH] Queue=>Double ended queue

---
 Queue=>Double ended queue | 241 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 241 insertions(+)
 create mode 100644 Queue=>Double ended queue

diff --git a/Queue=>Double ended queue b/Queue=>Double ended queue
new file mode 100644
index 0000000..4401ffa
--- /dev/null
+++ b/Queue=>Double ended queue	
@@ -0,0 +1,241 @@
+#include<stdio.h>
+#include<conio.h>
+
+void insertAtBeginning(int);
+void insertAtEnd(int);
+void insertAtAfter(int,int);
+void deleteBeginning();
+void deleteEnd();
+void deleteSpecific(int);
+void display();
+
+struct Node
+{
+   int data;
+   struct Node *previous, *next;
+}*head = NULL;
+
+void main()
+{
+   int choice1, choice2, value, location;
+   clrscr();
+   while(1)
+   {
+      printf("\n*********** MENU *************\n");
+      printf("1. Insert\n2. Delete\n3. Display\n4. Exit\nEnter your choice: ");
+      scanf("%d",&choice1);
+      switch()
+      {
+         case 1: printf("Enter the value to be inserted: ");
+         		 scanf("%d",&value);
+                 while(1)
+                 {
+                 	printf("\nSelect from the following Inserting options\n");
+                 	printf("1. At Beginning\n2. At End\n3. After a Node\n4. Cancel\nEnter your choice: ");
+                    scanf("%d",&choice2);
+                    switch(choice2)
+                    {
+                       case 1: 	insertAtBeginning(value);
+                       		break;
+                       case 2: 	insertAtEnd(value);
+                       		break;
+                       case 3: 	printf("Enter the location after which you want to insert: ");
+                       		scanf("%d",&location);
+                       		insertAfter(value,location);
+                       		break;
+                       case 4: 	goto EndSwitch;
+                       default: printf("\nPlease select correct Inserting option!!!\n");
+                    }
+                 }
+         case 2: while(1)
+                 {
+                 	printf("\nSelect from the following Deleting options\n");
+                 	printf("1. At Beginning\n2. At End\n3. Specific Node\n4. Cancel\nEnter your choice: ");
+                    scanf("%d",&choice2);
+                    switch(choice2)
+                    {
+                       case 1: 	deleteBeginning();
+                       		break;
+                       case 2: 	deleteEnd();
+                       		break;
+                       case 3: 	printf("Enter the Node value to be deleted: ");
+                       		scanf("%d",&location);
+                       		deleteSpecic(location);
+                       		break;
+                       case 4:	goto EndSwitch;
+                       default: printf("\nPlease select correct Deleting option!!!\n");
+                    }
+                 }
+                 EndSwitch: break;
+         case 3: display();
+         	 break;
+         case 4: exit(0);
+         default: printf("\nPlease select correct option!!!");
+      }
+   }
+}
+
+void insertAtBeginning(int value)
+{
+    struct Node *newNode;
+    newNode = (struct Node*)malloc(sizeof(struct Node));
+    newNode -> data = value;
+    newNode -> previous = NULL;
+    if(head == NULL)
+    {
+       newNode -> next = NULL;
+       head = newNode;
+    }
+    else
+    {
+       newNode -> next = head;
+       head = newNode;
+    }
+    printf("\nInsertion success!!!");
+}
+void insertAtEnd(int value)
+{
+   struct Node *newNode;
+   newNode = (struct Node*)malloc(sizeof(struct Node));
+   newNode -> data = value;
+   newNode -> next = NULL;
+   if(head == NULL)
+   {
+      newNode -> previous = NULL;
+      head = newNode;
+   }
+   else
+   {
+      struct Node *temp = head;
+      while(temp -> next != NULL)
+         temp = temp -> next;
+      temp -> next = newNode;
+      newNode -> previous = temp;
+   }
+   printf("\nInsertion success!!!");   
+}
+void insertAfter(int value, int location)
+{
+   struct Node *newNode;
+   newNode = (struct Node*)malloc(sizeof(struct Node));
+   newNode -> data = value;
+   if(head == NULL)
+   {
+      newNode -> previous = newNode -> next = NULL;
+      head = newNode;
+   }
+   else
+   {
+      struct Node *temp1 = head, temp2;
+      while(temp1 -> data != location)
+      {
+         if(temp1 -> next == NULL)
+         {
+            printf("Given node is not found in the list!!!");
+            goto EndFunction;
+         }
+         else
+         {
+            temp1 = temp1 -> next;
+         }
+      }
+      temp2 = temp1 -> next;
+      temp1 -> next = newNode;
+      newNode -> previous = temp1;
+      newNode -> next = temp2;
+      temp2 -> previous = newNode;
+      printf("\nInsertion success!!!");
+   }
+   EndFunction:
+}
+void deleteBeginning()
+{
+   if(head == NULL)
+      printf("List is Empty!!! Deletion not possible!!!");
+   else
+   {
+      struct Node *temp = head;
+      if(temp -> previous == temp -> next)
+      {
+         head = NULL;
+         free(temp);
+      }
+      else{
+         head = temp -> next;
+         head -> previous = NULL;
+         free(temp);
+      }
+      printf("\nDeletion success!!!");
+   }
+}
+void deleteEnd()
+{
+   if(head == NULL)
+      printf("List is Empty!!! Deletion not possible!!!");
+   else
+   {
+      struct Node *temp = head;
+      if(temp -> previous == temp -> next)
+      {
+         head = NULL;
+         free(temp);
+      }
+      else{
+         while(temp -> next != NULL)
+            temp = temp -> next;
+         temp -> previous -> next = NULL;
+         free(temp);
+      }
+      printf("\nDeletion success!!!");
+   }
+}
+void deleteSpecific(int delValue)
+{
+   if(head == NULL)
+      printf("List is Empty!!! Deletion not possible!!!");
+   else
+   {
+      struct Node *temp = head;
+      while(temp -> data != delValue)
+      {
+         if(temp -> next == NULL)
+         {
+            printf("\nGiven node is not found in the list!!!");
+            goto FuctionEnd;
+         }
+         else
+         {
+            temp = temp -> next;
+         }
+      }
+      if(temp == head)
+      {
+         head = NULL;
+         free(temp);
+      }
+      else
+      {
+         temp -> previous -> next = temp -> next;
+         free(temp);   
+      }
+      printf("\nDeletion success!!!");
+   }
+   FuctionEnd:
+}
+void display()
+{
+   if(head == NULL)
+      printf("\nList is Empty!!!");
+   else
+   {
+      struct Node *temp = head;
+      printf("\nList elements are: \n");
+      printf("NULL <--- ");
+      while(temp -> next != NULL)
+      {
+         printf("%d <===> ",temp -> data);
+      }
+      printf("%d ---> NULL", temp -> data);
+   }
+}
+______________________________