using System;

​

public class Program

{

    class Temp

    {

        public int ? A

        {

            get;

            set;

        }

    }

​

    public static void Main()

    {

        Temp obj = new Temp();

        int resultingValue1 = (obj.A == null || obj.A == default (int)) ? 3 : (int)obj.A;

        // or

        int resultingValue2 = obj.A.IsNullEmpty() ? 3 : (int)obj.A;

    }

}

​

public static class Extensions

{

    public static bool IsNullEmpty<T>(this T valueToCheck)

    {

        return valueToCheck == null || System.Collections.Generic.EqualityComparer<T>.Default.Equals(valueToCheck, default (T));

    }

}