using System;

class Program
{
	private interface ISomeType
	{
	}

	private class SomeType : ISomeType
	{
	}


	private static void DoWorkingSwap<TItem>(TItem[] array)
	{
		var temp = array[0];
		array[0] = array[1];
		array[1] = temp;
	}


	private static void Swap<TItem>(ref TItem firstItem, ref TItem secondItem)
	{
		var temp = firstItem;
		firstItem = secondItem;
		secondItem = temp;
	}

	private static void DoFaultySwap<TItem>(TItem[] array)
	{
		Swap(ref array[0], ref array[1]);
	}


	private static void Main(string[] args)
	{
		// ВАЖНО: обратите внимание на тип переменной под массив и тип самого массива
		ISomeType[] array = new SomeType[2] 
		{
			new SomeType(),
			new SomeType()
		};

		Console.Write("Doing working swap... ");
		try
		{
			DoWorkingSwap(array);
			Console.WriteLine("succeeded.");
		}
		catch (Exception ex)
		{
			Console.WriteLine("FAILED: {0}", ex);
		}

		Console.Write("Doing faulty swap... ");
		try
		{
			DoFaultySwap(array);
			Console.WriteLine("succeeded.");
		}
		catch (Exception ex)
		{
			Console.WriteLine("FAILED: {0}", ex);
		}
	}
}