using System;

using System.Collections.Generic;

public class Program

{

    public static void Main()

    {

        var fourDifferentNullableDecimals = new decimal?[4];

        for (var i = 0; i < fourDifferentNullableDecimals.Length; i++)

        {

            // Reset the last position tested, if applicable

            var j = i - 1;

            if (j >= 0)

            {

                fourDifferentNullableDecimals[j] = null;

            }

            // Set the current position to a non-null that can be differentited from the others

            fourDifferentNullableDecimals[i] = 1M + i;

            var result = fourDifferentNullableDecimals[0] ?? fourDifferentNullableDecimals[1] ?? fourDifferentNullableDecimals[2] ?? fourDifferentNullableDecimals[3];

            Console.WriteLine($"Position: {i}, Result: {result}");

        }

    }

}