using System;

using System.Linq;

using System.Collections.Generic;

public class Program

{

    public static void Main()

    {

        List<int> runData = null;

        if (runData != null && runData.Count > 0)

            Console.WriteLine("test 1 not null"); 

        else

            Console.WriteLine("test 1 null");   

        if (runData?.Count > 0)

            Console.WriteLine("test 2 not null"); 

        else

            Console.WriteLine("test 2 null"); 

        runData = new List<int>();

        runData.Add(1);

        if (runData != null && runData.Count > 0)

            Console.WriteLine("test 3 not null"); 

        else

            Console.WriteLine("test 3 null");   

        if (runData?.Count > 0)

            Console.WriteLine("test 4 not null"); 

        else

            Console.WriteLine("test 4 null"); 

    }

}