KundennummerMethoden.java

import java.util.Scanner;
public class KundennummerMethoden
{
    private static String getKDNR(int value)
    {
        StringBuilder buf = new StringBuilder();
        int count = 0, real_value, i, rest = 0;
        if(value < 0) value = -value;
        value = value%10000000;
        real_value = value;
        while(real_value > 0)
        {
            real_value /= 10;
            count++;
        }
        count = count == 0?6:(7-count);
        for(i = 0; i < count; i++)
        {
            buf.append('0');
        }
        buf.append(value);
        real_value = value;
        while(real_value > 0)
        {
            rest += (real_value%10);
            real_value /= 10;
        }
        rest = rest%10;
        if(rest > 0) rest = 10-rest;
        buf.append(rest);
        return buf.toString();
    }
    public static void main(String args[])
    {
        int kdnr;
        Scanner scanner = new Scanner(System.in);
        while(true)
        {
            System.out.print("Bitte geben Sie eine Kundennummer ein: ");
            kdnr = scanner.nextInt();
            System.out.println("Kundennummer: "+getKDNR(kdnr)+"\n--------------------\n\n");
        }
    }
}