What is a best way to increment alphanumeric ID by certain value in C#?

Question

What is a best way to increment alphanumeric ID by certain value in C#?

For example:

We've 345FAS310E575896325SA and we're going to increment by 123 , so we have as result: 345FAS310E575896325SA123

Or we've 345FAS310E575896325SA123 and increments by 234 , and result should be 345FAS310E575896325SA357

What is a "cheapest" way to make it work?

Answer 1

This is my algorithm:

    static void Main(string[] args)
    {
        var id = "843342D4343DA123D";
        var intSummand = 10;
        Console.WriteLine(AddToStringId(id, intSummand));
        Console.ReadKey();
    }

    static string AddToStringId(string id, int summand)
    {                         
        // set the begin-pointer of for the number to the end of the original id
        var intPos = id.Length;
        // go back from end of id to the begin while a char is a number
        for (int i = id.Length - 1; i >= 0; i--)
        {
            var charTmp = id.Substring(i, 1).ToCharArray()[0];
            if (char.IsNumber(charTmp))
            {
                // set the position one element back
                intPos--;
            }
            else
            {
                // we found a char and so we can break up
                break;
            }
        }
        var numberString = string.Empty;
        if (intPos < id.Length)
        {
            // the for-loop has found at least one numeric char at the end
            numberString = id.Substring(intPos, id.Length - intPos);
        }
        if (numberString.Length == 0)
        {
            // no number was found at the and so we simply add the summand as string
            id += summand.ToString();
        }
        else
        {
            // cut off the id-string up to the last char before the number at the end
            id = id.Substring(0, id.Length - numberString.Length);
            // add the Increment-operation-result to the end of the id-string and replace
            // the value which stood there before
            id += (int.Parse(numberString) + summand).ToString();
        }
        // return the result
        return id;
    }

Answer 2

The problem everyone is having here is that your Alphanumeric value doesnt really mean anything.

When you give your examples you are just adding numbers onto the end and incrementing those, you havent really given us any information about what the letters represent.

To be able to increment a value like this we need to know what the value of the letters are, a good example would be HEX, 0 - 9 A - F so if you were to say increment the HEX value 09 by 1 you would get 0A and incrementing 0F by 1 gives 10

I know this isnt an answer but until you give us some real info on what you are aiming to achieve with this we cant really give an answer. Also maybe tell us what you are using this for / why AlphaNumeric etc?

Answer 3

By looking at your examples, I interpret it like this:

If no ids are suffixed, one should be appended. Else, the ID should be incremented.

private static void Main(string[] args)
{
    var id = IncrementId("345FAS310E575896325SA", 123); // AS310E575896325SA123
    var id2 = IncrementId(id, 234); //345FAS310E575896325SA357
}

public static string IncrementId(string value, int id)
{
    // you might want to use fixed length or something else
    int suffixPos = value.IndexOf("SA");

    // no id has been appended
    if (value.Length == suffixPos + 2)
        return value + id;

    // increment the existing id.
    var currentId = int.Parse(value.Substring(suffixPos + 2));
    currentId += id;
    return value.Substring(0, suffixPos + 2) + currentId;
}

Answer 4

A Substring method? Where you pass in the number you wish to increment by, it will get the substring of the incremented values and add them together?

What happens when the increment goes over 99?

Does it just append 100 to the end of the alphanumeric ID?

Also will the rest of the alphanumberic ID stay the same? i.e:

843342D4343DA123D 10

843342D4343DA123D 20