25 Algorithms library [algorithms]

25.10 Generalized numeric operations [numeric.ops]

25.10.8 Inclusive scan [inclusive.scan]

template<class InputIterator, class OutputIterator> constexpr OutputIterator inclusive_scan(InputIterator first, InputIterator last, OutputIterator result);
Effects: Equivalent to:
return inclusive_scan(first, last, result, plus<>());
template<class ExecutionPolicy, class ForwardIterator1, class ForwardIterator2> ForwardIterator2 inclusive_scan(ExecutionPolicy&& exec, ForwardIterator1 first, ForwardIterator1 last, ForwardIterator2 result);
Effects: Equivalent to:
return inclusive_scan(std::forward<ExecutionPolicy>(exec), first, last, result, plus<>());
template<class InputIterator, class OutputIterator, class BinaryOperation> constexpr OutputIterator inclusive_scan(InputIterator first, InputIterator last, OutputIterator result, BinaryOperation binary_op); template<class ExecutionPolicy, class ForwardIterator1, class ForwardIterator2, class BinaryOperation> ForwardIterator2 inclusive_scan(ExecutionPolicy&& exec, ForwardIterator1 first, ForwardIterator1 last, ForwardIterator2 result, BinaryOperation binary_op); template<class InputIterator, class OutputIterator, class BinaryOperation, class T> constexpr OutputIterator inclusive_scan(InputIterator first, InputIterator last, OutputIterator result, BinaryOperation binary_op, T init); template<class ExecutionPolicy, class ForwardIterator1, class ForwardIterator2, class BinaryOperation, class T> ForwardIterator2 inclusive_scan(ExecutionPolicy&& exec, ForwardIterator1 first, ForwardIterator1 last, ForwardIterator2 result, BinaryOperation binary_op, T init);
Let U be the value type of decltype(first).
Mandates: If init is provided, all of
  • binary_­op(init, init),
  • binary_­op(init, *first), and
  • binary_­op(*first, *first)
are convertible to T; otherwise, binary_­op(*first, *first) is convertible to U.
Preconditions:
  • If init is provided, T meets the Cpp17MoveConstructible (Table 28) requirements; otherwise, U meets the Cpp17MoveConstructible requirements.
  • binary_­op neither invalidates iterators or subranges, nor modifies elements in the ranges [first, last] or [result, result + (last - first)].
Effects: For each integer K in [0, last - first) assigns through result + K the value of
  • GENERALIZED_­NONCOMMUTATIVE_­SUM(
        binary_­op, init, *(first + 0), *(first + 1), ..., *(first + K))

    if init is provided, or
  • GENERALIZED_­NONCOMMUTATIVE_­SUM(
        binary_­op, *(first + 0), *(first + 1), ..., *(first + K))

    otherwise.
Returns: The end of the resulting range beginning at result.
Complexity: applications of binary_­op.
Remarks: result may be equal to first.
Note
:
The difference between exclusive_­scan and inclusive_­scan is that inclusive_­scan includes the input element in the sum.
If binary_­op is not mathematically associative, the behavior of inclusive_­scan may be nondeterministic.
— end note
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