using System;

using System.Text;

using System.Text.Json.Serialization;           

​

public sealed class SWEDSESSTransaction

{

 [JsonPropertyName("balanceAfterTransaction")]

        public SWEDSESSStatementBalanceReferenceSE BalanceAfterTransaction { get; set; }

}

​

public sealed class SWEDSESSStatementBalanceReferenceSE

    {

        [JsonPropertyName("balanceAmount")]

        public SWEDSESSAmount BalanceAmount { get; set; }

​

        [JsonPropertyName("balanceType")]

        public SWEDSESSBalanceReferenceSEType BalanceType { get; set; }

    }

​

public sealed class SWEDSESSAmount

    {

        [JsonPropertyName("amount")]

        public string AmountValue { get; set; }

​

        [JsonPropertyName("currency")]

        public string Currency { get; set; }

    }

​

    [JsonConverter(typeof(JsonStringEnumConverter))]

    public enum SWEDSESSBalanceReferenceSEType

    {

        interimBooked = 1,

        interimAvailable = 2

    }

​

​

​

public class Program

{

    public static void Main()

    {

        SWEDSESSTransaction transaction = new(){

            BalanceAfterTransaction = null

        };

        string stringSetToNull = null;

        string stringSetToEmpty = string.Empty;

        StringBuilder myStringBuilder = new StringBuilder("Hello World!");

        myStringBuilder.Append(" What a beautiful day.");

        Console.WriteLine(myStringBuilder);

        Console.WriteLine($"Length: {myStringBuilder.Length}");

        myStringBuilder.Append(stringSetToEmpty);

        myStringBuilder.Append(stringSetToNull);

        myStringBuilder.Append("");

        Console.WriteLine($"Length after adding different kinds of string.empty: {myStringBuilder.Length}");

        myStringBuilder.Append(" ");

        Console.WriteLine($"Length after single whitespace: {myStringBuilder.Length}");

        myStringBuilder.Append(transaction?.BalanceAfterTransaction);

        Console.WriteLine($"Length after adding null obj: {myStringBuilder.Length}");

    }

}