Function to generate alpha numeric sequence number based on input number

Question

I am trying to develope a routine in C# that will take a given input integer and return a 6 character alpha numeric string based on a predefined possible set of characters.

The possible characters to use are:

"0123456789ABCDEFGHJKLMNPQRSTUVWXYZ" (note that the letter "I" and "O" are not in the set.)

Therefore given the input of 1, the output should be "000001", input of 9 would output "000009", input of 10 would output "00000A", input of 12345 would output "000AP3", and so on.

I am having a hard time coming up with an elegant solution to this problem. I know I must be approaching this the hard way so I'm looking for some help.

Thanks!

I can see you want leading 0's, but how did you arrive at that AP3 from 12345? That is what is needed to come up with some solution. — Hans Keﬆing, Sep 23 '10 at 15:41
Have a look at [zBase32](http://mytenpennies.wikidot.com/blog:base-32-encoder) [("human-oriented base-32 encoding")](http://philzimmermann.com/docs/human-oriented-base-32-encoding.txt). — dtb, Sep 23 '10 at 15:43

score 7 · Accepted Answer · answered Sep 23 '10 at 15:48

7

int value = 12345;

string alphabet = "0123456789ABCDEFGHJKLMNPQRSTUVWXYZ";

var stack = new Stack<char>();
while (value > 0)
{
     stack.Push(alphabet[value % alphabet.Length]);
     value /= alphabet.Length;
}
string output = new string(stack.ToArray()).PadLeft(6, '0');

answered Sep 23 '10 at 15:48

LukeH

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Wow -- now that is an elegant solution. Thanks so much LukeH! – Richard West Sep 23 '10 at 16:05
in alphabet's string, I and O is missing :P – X-Coder Jul 21 '16 at 09:10
@X-Coder: Yes, they're deliberately omitted, the same as in the question. – LukeH Jul 21 '16 at 10:54

score 1 · Answer 2 · answered Sep 23 '10 at 15:42

1

The direct solution would simply be to iteratively divide your input value by N (the size of the character set), and take the remainder each time to index into the character set, and build up the output string character-by-character.

answered Sep 23 '10 at 15:42

Oliver Charlesworth

267,707
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score 0 · Answer 3 · answered Sep 23 '10 at 15:48

internal class Program {
    private static void Main(string[] args) {
        int value = 38;

        const string alphabet = "0123456789ABCDEFGHJKLMNPQRSTUVWXYZ";
        string result = ToBase(value, alphabet);
        Console.WriteLine(result);
    }

    private static string ToBase(int value, string alphabet) {
        if (value == 0) return alphabet[0].ToString();
        var result = new StringBuilder();
        while (value > 0) {
            int digit = value % alphabet.Length;
            value = (value - digit) / alphabet.Length;
            result.Insert(0, alphabet[digit]);
        }
        return result.ToString();
    }
}

you do zero-padding

score 0 · Answer 4 · answered Jul 21 '16 at 12:15

LukeH answer modified for Generating Alphanemuric to numeric and vice versa

    int value = 12345;

    string alphabet = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";

    var stack = new Stack<char>();
    while (value > 0)
    {
        int index = value % alphabet.Length;
        stack.Push(alphabet[index]);
        value /= alphabet.Length;
    }

    string output = new string(stack.ToArray()).PadLeft(6, '0');
    double intNumber = 0;
    int charPos = 0;
    for (var i = output.Length-1; i >=0;i--)
    {
        int val = output[i];
        if (val >= 48 && val <= 57)
            intNumber += (val - 48) * (Math.Pow(36, charPos++));
        else if (val >= 65 && val <= 90)
            intNumber += (val - 55) * (Math.Pow(36, charPos++));
    }

Function to generate alpha numeric sequence number based on input number

4 Answers4