26 Numerics library [numerics]

26.7 Generalized numeric operations [numeric.ops]

26.7.3 Inner product [inner.product]

template <class InputIterator1, class InputIterator2, class T> T inner_product(InputIterator1 first1, InputIterator1 last1, InputIterator2 first2, T init); template <class InputIterator1, class InputIterator2, class T, class BinaryOperation1, class BinaryOperation2> T inner_product(InputIterator1 first1, InputIterator1 last1, InputIterator2 first2, T init, BinaryOperation1 binary_op1, BinaryOperation2 binary_op2);

Effects: Computes its result by initializing the accumulator acc with the initial value init and then modifying it with acc = acc + (*i1) * (*i2) or acc = binary_op1(acc, binary_op2(*i1, *i2)) for every iterator i1 in the range [first1,last1) and iterator i2 in the range [first2,first2 + (last1 - first1)) in order.

Requires: T shall meet the requirements of CopyConstructible (Table [copyconstructible]) and CopyAssignable (Table [copyassignable]) types. In the ranges [first1,last1] and [first2,first2 + (last1 - first1)] binary_op1 and binary_op2 shall neither modify elements nor invalidate iterators or subranges.291

The use of fully closed ranges is intentional