Number of digits of a Long value

Question

Hi there,
I want to calculate the number of digits of Long value. My first idea was to use
Long l = 1010101101010101010L;
int lLength = l.toString().length();is there a better way to do this?
regards,
Olek

Answer 1

log10() gives a NaN for negative values. Via a char array the digits can easily be counted.
public class NumberOfDigits {
    public static void main(String[] args) {
     numberOfDigits(-10101010101l);
    public static void numberOfDigits(Long l) {
     System.out.println();
     System.out.println("Value: " + l);
     System.out.println("Via String: " + l.toString().length());
     System.out.println("Via log 10: " + (int) Math.ceil(Math.log10(l)));
     char[] chars = l.toString().toCharArray();
     int count = 0;
     for (char c : chars) {
         if (Character.isDigit(c)) {
          count++;
     System.out.println("Via chars: " + count);
     if (l < 0) {
         numberOfDigits(Math.abs(l));
}Piet