C# Start with "a" vs "an"

Question

I have tried to search for this topic but I was unable to find any results. My question is: is there any way to figure out the prefix of a word? Whether it is "an" or "a".

For example:

an apple
a house
an old house
an amazon
a vampire

So my input would be just the word and then a function would return the correct prefix.

You mean you input, is, say "old house" and you want to know which article to apply to it? — Damien_The_Unbeliever, Mar 30 '20 at 15:28
[programmatically-determine-whether-to-describe-an-object-with-a-or-an](https://stackoverflow.com/questions/4558437/programmatically-determine-whether-to-describe-an-object-with-a-or-an) has a number of answers, including in C# — Damien_The_Unbeliever, Mar 30 '20 at 15:31
FYI that is not a "prefix", that is an *indefinite article*. — Eric Lippert, Mar 30 '20 at 16:58

score 0 · Accepted Answer · answered Mar 30 '20 at 15:37

Let's assume that any word that begins with a vowel will be preceded by "an" and that all other words will be preceded by "a".

string getArticle(string forWord)
{
  var vowels = new List<char> { 'A', 'E', 'I', 'O', 'U' };

  var firstLetter = forWord[0];
  var firstLetterCapitalized = char.ToUpper(firstLetter);
  var beginsWithVowel = vowels.Contains(firstLetterCapitalized);

  if (beginsWithVowel)
    return "an";

  return "a";
}

Could this be simplified and improved? Of course. However, it should serve as somewhere from which to start.

Less readable but shorter versions exists, such as:

string getArticle(string forWord) => (new List<char> { 'A', 'E', 'I', 'O', 'U' }).Contains(char.ToUpper(forWord[0])) ? "an" : "a";

However, both of these ignore edge cases such as forWord being null or empty.

score 0 · Answer 2 · answered Mar 30 '20 at 15:38

The links in the comments give the most comprehensive reply but if you were after something very simple to understand the concept, it would be something like this:

To get the indefinite article (prefix) pass the noun:

    public static string prefix(string noun)
    {
        List<string> vowels = new List<string>(){ "A", "E", "I", "O", "U" };
        if (string.IsNullOrWhiteSpace(noun) || noun.Length < 2) return null;
        else return vowels.Contains(noun.Substring(0, 1).ToUpper()) ? "An" : "A";
    }

C# Start with "a" vs "an"

2 Answers2