methods: ref, out, default parameters

Program.cs

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

namespace csharp
{
    public class Program
    {
        static int b(int x = 2, int y = 1)
        {
            return x * y;
        }

        static void a(int i, ref int ii, out int iii, int x = 3)
        {
            i *= 2;
            ii *= x;
            //iii *= 4;
            iii = ii * 4;
        }

        static void Main(string[] args)
        {
            int i = 5;
            a(i, ref i, out i);
            Console.WriteLine(i);
            
            i = 5;
            a(i, ref i, out i, 2);
            Console.WriteLine(i);

            Console.WriteLine(b(y: 2));

            Console.ReadKey();
        }
    }
}