TestCsharpVersion

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace TestCsharpVersion
{
    class Program
    {
        //This should give an error since CSharp 3 does not support optional params
        private void TestOptionalParam(string myOptional = "foobar")
        {
        }

        static void Main(string[] args)
        {
            //Example from http://ericlippert.com/2009/11/12/closing-over-the-loop-variable-considered-harmful-part-one/
            //For C# version 5 this should return 100, 110, 120 and for C# version 4 or lower this should return 120, 120, 120
            var values = new List<int>() { 100, 110, 120 };
            var funcs = new List<Func<int>>();
            foreach (var v in values)
                funcs.Add(() => v);
            foreach (var f in funcs)
                Console.WriteLine(f());


            //Logic to check if we're on C# 5
            var testList = new List<string> { "a", "b" };
            var lambdas = new List<Func<string>>();
            var result = "";

            //Capture using foreach
            foreach (var test in testList)
            {
                lambdas.Add(() => test);
            }

            //Read the captured vars
            foreach (var lamdba in lambdas)
            {
                result += lamdba();
            }

            //Check if it's C# 5 behavior
            if (result == "ab")
            {
                result = "This is C# 5 or higher";
            }
            else if (result == "bb")
            {
                result = "This is C# 4 or lower";
            }
            else
            {
                result = "Unexpected result, no idea which C# version";
            }

            Console.WriteLine(result);
            Console.ReadLine();
        }
    }
}