medium article 1

Iban.cs

public class Iban {
  private readonly string plainIban;

  private Iban(string iban) {
    if (!Validate(iban)) throw new ArgumentException();
    plainIban = iban;
  }

  private bool Validate(string ibanToValidate) {
    // validation (check length, validate check digits and sum, etc.)
    return true;
  }
    
  public static implicit operator Iban(string iban) {
      return new Iban(iban);
  }
}

/*
* Client code can use it like below
*/

Iban account = "DK5000400440116243" // <- validation now runs on the string aswell
WithdrawMoney(account, 100);
WithdrawMoney("DK5000400440116243", 100);