C# Online Compiler | .NET Fiddle

using System;

public class Program
{
	public static void Main()
	{
		int option = 2;
		switch (option)
		{
			case 1:
			{
				string msg = "selected one";
				Console.WriteLine($"Hello World :{msg}");
				break;
			}

			case 2:
			{
				string msg = "selected two";
				Console.WriteLine($"Hello World :{msg}");
				break;
			}

			default:
			{
				string msg = "nothing selected.so default";
				Console.WriteLine($"Hello World :{msg}");
				break;
			}
		}
	}
}

 
using System;
​
public class Program
{
    public static void Main()
    {
        int option = 2;
        switch (option)
        {
            case 1:
            {
                string msg = "selected one";
                Console.WriteLine($"Hello World :{msg}");
                break;
            }
​
            case 2:
            {
                string msg = "selected two";
                Console.WriteLine($"Hello World :{msg}");
                break;
            }
​
            default:
            {
                string msg = "nothing selected.so default";
                Console.WriteLine($"Hello World :{msg}");
                break;
            }
        }
    }
}