Fix iiitv#501: Add Stack [C#] (iiitv#502)

* Added Stack [C#]

* fixed intendation

* forgot one whitespace...

* Added Main method

* An attempt to fix travis issues

* Removed Swap and Duplicate methods

* Edited pop method, added toString method and added prints

* Small change

* Change comments and fixed trailing whitespace

README.md

@@ -56,7 +56,7 @@ Community (college) maintained list of Algorithms and Data Structures implementa
 | [AVL Tree](http://www.geeksforgeeks.org/avl-tree-set-1-insertion)| | |[:white_check_mark:](avl_tree/AvlTree.java) | | | | |
 | [Binary Search Tree](https://en.wikipedia.org/wiki/Binary_search_tree) | | | [:white_check_mark:](binary_search_tree/BinarySearchTree.java) | | | | |
 | [Linked List](https://en.wikipedia.org/wiki/Linked_list) | [:white_check_mark:](linked_list/linkedList.c.c) | | [:white_check_mark:](linked_list/LinkedList.java) | [:white_check_mark:](linked_list/linked_list.py) | [:white_check_mark:](linked_list/linked_list.go) | [:white_check_mark:](linked_list/linkedList.js) | [:white_check_mark:](linked_list/LinkedList.cs) |
-| [Stack](https://en.wikipedia.org/wiki/Stack_(abstract_data_type)) | [:white_check_mark:](stack/stack.c) | | [:white_check_mark:](stack/Stack.java) | [:white_check_mark:](stack/stack.py) | [:white_check_mark:](stack/stack.go) | [:white_check_mark:](stack/stack.js) | |
+| [Stack](https://en.wikipedia.org/wiki/Stack_(abstract_data_type)) | [:white_check_mark:](stack/stack.c) | | [:white_check_mark:](stack/Stack.java) | [:white_check_mark:](stack/stack.py) | [:white_check_mark:](stack/stack.go) | [:white_check_mark:](stack/stack.js) | [:white_check_mark:](stack/Stack.cs) |
 | [Trie](https://en.wikipedia.org/wiki/Trie) | | [:white_check_mark:](trie/trie.cpp) | [:white_check_mark:](trie/Trie.java) | | | | | |
 
 

stack/Stack.cs

@@ -0,0 +1,149 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+
+class MainClass
+{
+    public static void Main()
+    {
+        Stack<string> test = new Stack<string>();
+
+        test.Push("123");
+        test.Push("test");
+        test.Push("rawr");
+        test.Push("Pancake");
+        test.Push("Yummy");
+        test.Push("321");
+        test.Push(":thinking:");
+
+        Console.WriteLine(test.ToString());
+
+        test.Rotate(4, true);
+
+        Console.WriteLine(test.ToString());
+
+        test.Rotate(5, false);
+
+        Console.WriteLine(test.ToString());
+
+        Console.WriteLine(test.Peek() + "\n");
+
+        while (!(test.IsEmpty()))
+        {
+            test.Pop();
+            Console.WriteLine(test.ToString());
+        }
+    }
+}
+
+class Stack<T>
+{
+    private LinkedList<T> stack;
+
+    // Constructs an empty stack
+    public Stack()
+    {
+        stack = new LinkedList<T>();
+    }
+
+    // Adds element at the top of the stack
+    public void Push(T data)
+    {
+        stack.AddLast(data);
+    }
+
+    // Removes the element at the top of the stack
+    public T Pop()
+    {
+        if (IsEmpty())
+            return default(T);
+
+        T element = stack.Last();
+
+        stack.RemoveLast();
+
+        return element;
+    }
+
+    // Returns true if the stack is empty
+    public bool IsEmpty()
+    {
+        return (!stack.Any());
+    }
+
+
+    // Returns the last element of the stack
+    public T Peek()
+    {
+        if (IsEmpty())
+            return default(T);
+
+        return stack.Last();
+    }
+
+    /**
+    * gets the n top elements and rotates them
+    *
+    * if left == false then it will move the last element to behind the nth element(from the top)
+    *
+    * if left == true it will move the nth element(from the top) to the top
+    */
+    public void Rotate(int n, bool left)
+    {
+        if (n <= 1)
+            return;
+
+        if (stack.Count < 2)
+            return;
+
+        n -= 1;
+
+        if (left)
+        {
+            LinkedListNode<T> node = stack.Last;
+
+            for (int i = 1; i <= n; ++i)
+            {
+                node = node.Previous;
+            }
+
+            T value = node.Value;
+
+            stack.Remove(value);
+
+            Push(value);
+        }
+        else
+        {
+            T last = stack.Last();
+
+            Pop();
+
+            LinkedListNode<T> node = stack.Last;
+
+            for (int i = 0; i < n; i++)
+            {
+                node = node.Previous;
+            }
+
+            stack.AddBefore(node.Next, last);
+        }
+    }
+
+    public override string ToString()
+    {
+        string s = "Stack: ";
+
+        foreach(T t in stack)
+        {
+            s += t.ToString() + " | ";
+        }
+
+        s += "\n";
+
+        return s;
+    }
+}