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!

Answer 1

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');

Answer 2

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.