Sum digits of an integer

Sum digits of an integer is a draft programming task. It is not yet considered ready to be promoted as a complete task, for reasons that should be found in its talk page.

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>

1. 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;

}</lang>

Produces:

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

Ruby

<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>