#587 – If Provided, Optional Arguments Must Be in Correct Order

When you choose to include arguments for optional parameters on a method, you must specify the arguments in the proper order (just like required parameters).

In the example below, we define a method with one required parameter and three optional parameters.  When we call it, we must provide a value for the yourName parameter.  Then we can provide values for one, two or all three of the optional parameters, in the following combinations:

  • book
  • book, play
  • book, play, poem
        static void Favorites(
            string yourName,
            string book = "Moby Dick",
            string play = "Henry V",
            string poem = "The Road Not Taken")
        {
            Console.WriteLine("{0}'s favorites:", yourName);
            Console.WriteLine("  Book: {0}", book);
            Console.WriteLine("  Play: {0}", play);
            Console.WriteLine("  Poem: {0}", poem);
        }

        static void Main()
        {
            Favorites("Sean");
            Favorites("Sergei", "Anna Karenina");
            Favorites("Pablo", "Don Quixote", "Canción de cuna");
            Favorites("Nigel", "David Copperfield", "Hamlet", "Ode to Duty");
        }

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About Sean
Software developer in the Twin Cities area, passionate about .NET technologies. Equally passionate about my own personal projects related to family history and preservation of family stories and photos.

One Response to #587 – If Provided, Optional Arguments Must Be in Correct Order

  1. Pingback: #693 – Named Arguments in Constructors Allow the Most Flexibility « 2,000 Things You Should Know About C#

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