Sum digits of an integer

This task takes a Natural Number in a given Base and returns the sum of it digits:

1 sums to 1;

1234 sums to 10;

0xfe sums to 29;

0xf0e sums to 29.

C++

<lang cpp>#include <iostream>

include <cmath>

int SumDigits(const int digits, const int BASE = 10) {

       int sum = 0;
       int x = digits;
       for (int i = log(digits)/log(BASE); i>0; i--) {
               const int z = pow(BASE, i);
               const int t = x / z;
               sum += t;
               x -= t * z;
       }
       return x + sum;

}

int main() {

       std::cout << SumDigits(1) << ' '
                 << SumDigits(12345) << ' '
                 << SumDigits(123045) << ' '
                 << SumDigits(0xfe, 16) << ' '
                 << SumDigits(0xf0e, 16) << std::endl;
       return 0;

}</lang>

Output:

1 15 15 29 29

Erlang

<lang erlang> -module(sum_digits). -export([sum_digits/2, sum_digits/1]).

sum_digits(N) ->

   sum_digits(N,10).

sum_digits(N,B) ->

   sum_digits(N,B,0).

sum_digits(0,_,Acc) ->

   Acc;

sum_digits(N,B,Acc) when N < B ->

   Acc+N;

sum_digits(N,B,Acc) ->

   sum_digits(N div B, B, Acc + (N rem B)).

</lang>

Example usage:

2> sum_digits:sum_digits(1).
1
3> sum_digits:sum_digits(1234).
10
4> sum_digits:sum_digits(16#fe,16).
29
5> sum_digits:sum_digits(16#f0e,16).
29

Java

<lang java>public class SumDigits {

   public static int sumDigits(long num) {

return sumDigits(num, 10);

   }
   public static int sumDigits(long num, int base) {

String s = Long.toString(num, base); int result = 0; for (int i = 0; i < s.length(); i++) result += Character.digit(s.charAt(i), base); return result;

   public static void main(String[] args) {

System.out.println(sumDigits(1)); System.out.println(sumDigits(12345)); System.out.println(sumDigits(123045)); System.out.println(sumDigits(0xfe, 16)); System.out.println(sumDigits(0xf0e, 16));

}</lang>

Output:

<lang ruby>>> def sumDigits(num, base = 10) >> num.to_s(base).split(//).inject(0) {|z, x| z + x.to_i(base)} >> end => nil >> sumDigits(1) => 1 >> sumDigits(12345) => 15 >> sumDigits(123045) => 15 >> sumDigits(0xfe, 16) => 29 >> sumDigits(0xf0e, 16) => 29 </lang>

C++

Erlang

Java

Ruby