Indefinite article for word

gistfile1.txt

- (NSString *)indefiniteArticleForWord:(NSString *)word singularArticle:(NSString *)singularArticle pluralArticle:(NSString *)pluralArticle
{
    NSString *firstLetter = [[word lowercaseString] substringToIndex:1];
    NSArray *vowels = @[@"a",@"e",@"i",@"o",@"u"];
    BOOL isFirstLetterVowel = NO;
    
    for (NSString *vowel in vowels){
        if ([vowel isEqualToString:firstLetter]) {
            isFirstLetterVowel = YES;
            break;
        }
    }
    
    if (isFirstLetterVowel) {
        return pluralArticle;
    } else {
        return singularArticle;
    }
}

- (NSString *)indefiniteArticleForWord:(NSString *)word singularArticle:(NSString *)singularArticle pluralArticle:(NSString *)pluralArticle
{
    NSString *firstLetter = [[word lowercaseString] substringToIndex:1];
    NSArray *vowels = @[@"a",@"e",@"i",@"o",@"u"];

    return ([vowels containsObject:firstLetter] ? pluralArticle : singularArticle);
}

- (NSString *)indefiniteArticleForWord:(NSString *)word singularArticle:(NSString *)singularArticle pluralArticle:(NSString *)pluralArticle
{
    unichar *firstLetter = [[word lowercaseString] characterAtIndex:1];

    switch (firstLetter)
    {
        case 'a': case 'e': case 'i': case 'o': case: 'u':
            return pluralArticle;

        default:
            return singularArticle;
    }
}

- (NSString *)indefiniteArticleForWord:(NSString *)word singularArticle:(NSString *)singularArticle pluralArticle:(NSString *)pluralArticle
{
    NSString *firstLetter = [[word lowercaseString] substringToIndex:1];
    NSArray *vowels = @[@"a",@"e",@"i",@"o",@"u", firstLetter];

    return ([vowels containsObject:firstLetter] ? pluralArticle : singularArticle);
}