algorithm/cxx17/transform_reduce.hpp

0001 /*
0002    Copyright (c) Marshall Clow 2017.
0003
0004    Distributed under the Boost Software License, Version 1.0. (See accompanying
0005    file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
0006 */
0007
0008 /// \file  transform_reduce.hpp
0009 /// \brief Combine the (transformed) elements of a sequence (or two) into a single value.
0010 /// \author Marshall Clow
0011
0012 #ifndef BOOST_ALGORITHM_TRANSFORM_REDUCE_HPP
0013 #define BOOST_ALGORITHM_TRANSFORM_REDUCE_HPP
0014
0015 #include <functional>     // for std::plus
0016 #include <iterator>       // for std::iterator_traits
0017
0018 #include <boost/config.hpp>
0019 #include <boost/range/begin.hpp>
0020 #include <boost/range/end.hpp>
0021 #include <boost/range/value_type.hpp>
0022
0023 namespace boost { namespace algorithm {
0024
0025 template<class InputIterator1, class InputIterator2, class T,
0026          class BinaryOperation1, class BinaryOperation2>
0027 T transform_reduce(InputIterator1 first1, InputIterator1 last1,
0028                    InputIterator2 first2, T init,
0029                  BinaryOperation1 bOp1, BinaryOperation2 bOp2)
0030 {
0031     for (; first1 != last1; ++first1, (void) ++first2)
0032         init = bOp1(init, bOp2(*first1, *first2));
0033     return init;
0034 }
0035
0036 template<class InputIterator, class T,
0037          class BinaryOperation, class UnaryOperation>
0038 T transform_reduce(InputIterator first, InputIterator last,
0039                    T init, BinaryOperation bOp, UnaryOperation uOp)
0040 {
0041     for (; first != last; ++first)
0042         init = bOp(init, uOp(*first));
0043     return init;
0044 }
0045
0046 template<class InputIterator1, class InputIterator2, class T>
0047 T transform_reduce(InputIterator1 first1, InputIterator1 last1,
0048                    InputIterator2 first2, T init)
0049 {
0050     return boost::algorithm::transform_reduce(first1, last1, first2, init,
0051                             std::plus<T>(), std::multiplies<T>());
0052 }
0053
0054 }} // namespace boost and algorithm
0055
0056 #endif // BOOST_ALGORITHM_TRANSFORM_REDUCE_HPP