How Can I Efficiently Sum the Elements of a std::vector in C ?

Summation Techniques for Elements in a std::vector

Finding the sum of elements in a std::vector is a common operation. Here are various approaches:

C 03

• Classic For Loop:

  int sum_of_elems = 0;
  for (std::vector<int>::iterator it = vector.begin(); it != vector.end(); ++it)
    sum_of_elems += *it;

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• Standard Algorithm:

  #include <numeric>
  sum_of_elems = std::accumulate(vector.begin(), vector.end(), 0);

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C 11 and Above

• Automatic Type Tracking:

  #include <numeric>
  sum_of_elems = std::accumulate(vector.begin(), vector.end(),
                                decltype(vector)::value_type(0));

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• std::for_each:

  std::for_each(vector.begin(), vector.end(), [&] (int n) {
    sum_of_elems += n;
  });

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• Range-Based For Loop:

  for (auto& n : vector)
    sum_of_elems += n;

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C 17 and Above

• std::reduce:

  #include <numeric>
  auto result = std::reduce(v.begin(), v.end());

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This function infers the result type based on the vector's element type, allowing for automatic handling of different numeric types.

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