CODEWITHSUNDEEP
c#char
Loj
Loj

Reputation: 1189

Incrementation of char

I found some question asking how to let char 'B' to return 'C' and then 'D' etc. The answers were quite complex and mostly just overkill.

Why not to use simply this:

char X='A';
X++;

EDIT: It goes from A to Z and what next?

Upvotes: 25

Views: 38973

Answers (3)

kerrubin
kerrubin

Reputation: 1616

If you just want to increment :

Char x = 'A';
Char y = (Char)(Convert.ToUInt16(x) + 1);

But, if you want an excel like column :

    // (1 = A, 2 = B...27 = AA...703 = AAA...)
    public static string GetColNameFromIndex(int columnNumber)
    {
        int dividend = columnNumber;
        string columnName = String.Empty;
        int modulo;

        while (dividend > 0)
        {
            modulo = (dividend - 1) % 26;
            columnName = Convert.ToChar(65 + modulo).ToString() + columnName;
            dividend = (int)((dividend - modulo) / 26);
        }

        return columnName;
    }

    // (A = 1, B = 2...AA = 27...AAA = 703...)
    public static int GetColNumberFromName(string columnName)
    {
        char[] characters = columnName.ToUpperInvariant().ToCharArray();
        int sum = 0;
        for (int i = 0; i < characters.Length; i++)
        {
            sum *= 26;
            sum += (characters[i] - 'A' + 1);
        }
        return sum;
    }

Upvotes: 45

Jon Skeet
Jon Skeet

Reputation: 1504052

If you're happy with the results that gives, then that's fine.

Usually when I've seen questions like that, they want to wrap from "Z" to "AA" or something like that that though - like Excel columns. Clearly just incrementing a char won't do that - it would go to '['.

Alternatively, even within a single character, the range of valid values may be non-contiguous - the obvious example being hex. If you increment '9' you get ':' instead of the 'a' or 'A' which you probably wanted. The desired order is rarely "whatever Unicode gives you".

Upvotes: 24

Matthew Flaschen
Matthew Flaschen

Reputation: 285077

Probably because it is also intended to go from Z to AA, ala Perl and PHP.

Upvotes: 1

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