Sum of digits (tools/digit_sum.hpp)

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• Last update: 2022-05-29 19:05:22+09:00
• Include: #include "tools/digit_sum.hpp"

template <typename T>
T digit_sum(T n);

It returns sum of the digits of $n$.

Constraints

• $n \geq 0$

Time Complexity

• $O\left(\log n\right)$

License

• CC0

Author

• anqooqie

Verified with

• tests/digit_sum.test.cpp

Code

#ifndef TOOLS_DIGIT_SUM_HPP
#define TOOLS_DIGIT_SUM_HPP

#include <cassert>

namespace tools {

  template <typename T>
  T digit_sum(T n) {
    assert(n >= 0);
    T sum = 0;
    for (; n > 0; n /= 10) {
      sum += n % 10;
    }
    return sum;
  }
}

#endif

#line 1 "tools/digit_sum.hpp"



#include <cassert>

namespace tools {

  template <typename T>
  T digit_sum(T n) {
    assert(n >= 0);
    T sum = 0;
    for (; n > 0; n /= 10) {
      sum += n % 10;
    }
    return sum;
  }
}

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