Addition of QueueBasedStack

[manish0x0f]

I have gone through repo and noticed there is StackBasedQueue but not QueueBasedStack.It is possible to implement stack using queue but Pop operation time complexity is O(n).But for completeness if it is okay I can add QueueBasedStack with a pull request.

public class QueueBasedStack<T>
    {
        private readonly Queue<T> queue;

        public QueueBasedStack() => queue = new Queue<T>();

        /// <summary>
        ///     Clears the stack
        /// </summary>
        public void Clear() => queue.Clear();

        public bool IsEmpty() => queue.Count == 0;

        /// <summary>
        ///     Adds an item on top of the stack
        /// </summary>
        /// <param name="item">Item to be added on top of stack</param>
        public void Push(T item) => queue.Enqueue(item);

        /// <summary>
        ///     Removes an item from  top of the stack and returns it 
        /// </summary>
        /// <returns>item on top of stack</returns>
        /// <exception cref="InvalidOperationException">Throw if stack is empty</exception>
        public T Pop()
        {
            if(IsEmpty())
            {
                throw new InvalidOperationException("The stack contains no items.");
            }
            for (int i = 0; i < queue.Count - 1; i++)
            {
                queue.Enqueue(queue.Dequeue());
            }
            return queue.Dequeue();
        }

        /// <summary>
        ///     return an item from the top of the stack without removing it
        /// </summary>
        /// <returns>item on top of the stack</returns>
        /// <exception cref="InvalidOperationException">Throw if stack is empty</exception>
        public T Peek()
        {
            if(IsEmpty())
            {
                throw new InvalidOperationException("The stack contains no items.");
            }
            for (int i = 0; i < queue.Count - 1; i++)
            {
                queue.Enqueue(queue.Dequeue());
            }
            var item = queue.Peek();
            queue.Enqueue(queue.Dequeue());
            return item;

        }

        /// <summary>
        ///     returns the count of items on the stack
        /// </summary>
        /// <returns>number of items on the stack</returns>
        public int Length() => queue.Count;

    }

[Andrii Siriak]

Sure, let's add it

[manish0x0f]

I submitted a pull request #412 for adding Queue based Stack.

[Andrii Siriak]

Done