C# 7.1 New Features - https://codingblast.com/csharp-7-1-new-features/

CSharp71.cs

using System;

namespace CSharp71Features
{
	class Program
	{
		static void Main(string[] args)
		{
			DoSomething();
		}


		static void DoSomething(string text = default(string))
		{
			int myNumber = default(int);

			Console.WriteLine(myNumber);
			Console.WriteLine($"text:{text}");
		}
	}
}