Added a imoplementation of Double ended Queue

samples/Double_Ended_Queue.cpp

@@ -0,0 +1,91 @@
+/*Author Alok Khulbay
+Date:12/10/2020.
+Algorithm for the Implementation:
+Begin
+   Declare a class dequeue to declare front f and rear r and following functions:
+   function insert_at_beg(int) to insert item at front:
+      If queue is not completely filled up, insert element at the front and update front and rear
+      Otherwise print overflow.
+   function insert_at_end(int) to insert item at rear:
+      If queue is not completely filled up, insert element at the rear and update front and rear
+      Otherwise print overflow.
+   function delete_fr_beg() to delete item from front:
+      If queue is empty, print underflow otherwise delete the front element and update front.
+   function delete_fr_end() to delete item from end:
+      If queue is empty, print underflow otherwise delete the rear element and update rear.
+End
+*/
+#include <iostream>
+#include <deque>
+#include <string>
+#include <cstdlib>
+#include <vector>
+int main()
+{
+    std::deque<int> d;
+    std::deque<int>::iterator it;
+    int c = 0, item = 0;
+    while (1)
+    {
+        std::cout << "1.Size of the Deque" << std::endl;
+        std::cout << "2.Insert Element at the End" << std::endl;
+        std::cout << "3.Insert Element at the Front" << std::endl;
+        std::cout << "4.Delete Element at the End" << std::endl;
+        std::cout << "5.Delete Element at the Front" << std::endl;
+        std::cout << "6.Front Element at the Deque" << std::endl;
+        std::cout << "7.Last Element at the Deque" << std::endl;
+        std::cout << "8.Display Deque" << std::endl;
+        std::cout << "9.Exit" << std::endl;
+        std::cout << "Enter your choice:";
+        std::cin >> c;
+        switch (c)
+        {
+        case 1:
+            std::cout << "Size of the Deque: " << d.size() << std::endl;
+            break;
+        case 2:
+            std::cout << "Enter value to be inserted at the End: " << std::endl;
+            std::cin >> item;
+            d.push_back(item);
+            break;
+        case 3:
+            std::cout << "Enter value to be inserted at the Front: " << std::endl;
+            std::cin >> item;
+            d.push_front(item);
+            break;
+        case 4:
+            item = d.back();
+            d.pop_back();
+            std::cout << "Element " << item << " Deleted" << std::endl;
+            break;
+        case 5:
+            item = d.front();
+            d.pop_front();
+            std::cout << "Element " << item << "Deleted" << std::endl;
+            break;
+        case 6:
+            std::cout << "Front Element of the Deque is: ";
+            std::cout << d.front() << std::endl;
+            break;
+        case 7:
+            std::cout << "Back Element of the Deque is: ";
+            std::cout << d.back() << std::endl;
+            break;
+        case 8:
+            std::cout << "Elements of Deque: ";
+            for (it = d.begin(); it != d.end(); it++)
+            {
+                std::cout << *it << " ";
+                std::cout << std::endl;
+            }
+            break;
+        case 9:
+            exit(1);
+            break;
+
+        default:
+            std::cout << "Wrong Choice" << std::endl;
+        }
+    }
+    return 0;
+}