(C++) accumulate_if

Algorithm similar to std::accumulate, except that accumulate_if also needs a predicate argument.

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//From http://www.richelbilderbeek.nl/CppAccumulate_if.htm template   <   typename InputIterator,   typename ElementType,   typename Predicate   > const ElementType accumulate_if(   InputIterator first,   const InputIterator last,   ElementType init,   const Predicate predicate) {   for (; first != last; ++first)     if (predicate(*first)) init += *first;   return init; }

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//From http://www.richelbilderbeek.nl/CppAccumulate_if.htm template   <   typename InputIterator,   typename ElementType,   typename BinaryOperation,   typename Predicate   > const ElementType std::accumulate_if(   InputIterator first,   const InputIterator last,   ElementType init,   const BinaryOperation binary_op,   const Predicate predicate) {   for (; first != last; ++first)     if (predicate(*first)) init = binary_op(init, *first);   return init; }