std::transform_inclusive_scan (3)  Linux Manuals
std::transform_inclusive_scan: std::transform_inclusive_scan
NAME
std::transform_inclusive_scan  std::transform_inclusive_scan
Synopsis
Defined in header <numeric>
template< class InputIt, class OutputIt,
class BinaryOperation, class UnaryOperation > (1) (since C++17)
OutputIt transform_inclusive_scan( InputIt first, InputIt last, OutputIt d_first,
BinaryOperation binary_op, UnaryOperation unary_op );
template< class ExecutionPolicy, class ForwardIt1, class ForwardIt2,
class BinaryOperation, class UnaryOperation >
ForwardIt2 transform_inclusive_scan( ExecutionPolicy&& policy, (2) (since C++17)
ForwardIt1 first, ForwardIt1 last, ForwardIt2 d_first,
BinaryOperation binary_op, UnaryOperation unary_op );
template< class InputIt, class OutputIt,
class BinaryOperation, class UnaryOperation, class T >
OutputIt transform_inclusive_scan( InputIt first, InputIt last, OutputIt d_first, (3) (since C++17)
BinaryOperation binary_op, UnaryOperation unary_op,
T init );
template< class ExecutionPolicy, class ForwardIt1, class ForwardIt2,
class BinaryOperation, class UnaryOperation, class T >
ForwardIt2 transform_inclusive_scan( ExecutionPolicy&& policy, (4) (since C++17)
ForwardIt1 first, ForwardIt1 last, ForwardIt2 d_first,
BinaryOperation binary_op, UnaryOperation unary_op,
T init );
Transforms each element in the range [first, last) with unary_op, then computes an inclusive prefix sum operation using binary_op over the resulting range, optionally with init as the initial value, and writes the results to the range beginning at d_first. "inclusive" means that the ith input element is included in the ith sum.
Formally, assigns through each iterator i in [d_first, d_first + (last  first)) the value of
* for overloads (12), the generalized noncommutative sum of unary_op(*j)... for every j in [first, first + (i  d_first + 1)) over binary_op,
* for overloads (34), the generalized noncommutative sum of init, unary_op(*j)... for every j in [first, first + (i  d_first + 1)) over binary_op,
where generalized noncommutative sum GNSUM(op, a
1, ..., a
N) is defined as follows:
* if N=1, a
* if N > 1, op(GNSUM(op, a
In other words, the summation operations may be performed in arbitrary order, and the behavior is nondeterministic if binary_op is not associative.
Overloads (2, 4) are executed according to policy, and do not participate in overload resolution unless std::is_execution_policy_v<std::decay_t<ExecutionPolicy>> is true.
unary_op and binary_op shall not invalidate iterators (including the end iterators) or subranges, nor modify elements in the ranges [first, last) or [d_first, d_first + (last  first)). Otherwise, the behavior is undefined.
Parameters
first, last  the range of elements to sum
d_first  the beginning of the destination range; may be equal to first
policy  the execution policy to use. See execution_policy for details.
init  the initial value
unary_op  unary FunctionObject that will be applied to each element of the input range. The return type must be acceptable as input to binary_op.
binary_op  binary FunctionObject that will be applied in to the result of unary_op, the results of other binary_op, and init if provided.
Type requirements

InputIt must meet the requirements of LegacyInputIterator.

OutputIt must meet the requirements of LegacyOutputIterator.

ForwardIt1 must meet the requirements of LegacyForwardIterator. and, if init is not provided, ForwardIt1's value_type must be MoveConstructible and binary_op(unary_op(*first), unary_op(*first)) must be convertible to ForwardIt1's value type

ForwardIt2 must meet the requirements of LegacyForwardIterator.

T (if init is provided) must meet the requirements of MoveConstructible. All of binary_op(init, unary_op(*first)), binary_op(init, init), and binary_op(unary_op(*first), unary_op(*first)) must be convertible to T
Return value
Iterator to the element past the last element written.
Complexity
O(last  first) applications of each of binary_op and unary_op.
Exceptions
The overloads with a template parameter named ExecutionPolicy report errors as follows:
* If execution of a function invoked as part of the algorithm throws an exception and ExecutionPolicy is one of the standard_policies, std::terminate is called. For any other ExecutionPolicy, the behavior is implementationdefined.
* If the algorithm fails to allocate memory, std::bad_alloc is thrown.
Notes
unary_op is not applied to init.
The parameter init appears last, differing from std::transform_exclusive_scan, because it is optional for this function.
Example
// Run this code
Output:
See also
partial_sum (function template)
transform (function template)
inclusive_scan similar to std::partial_sum, includes the ith input element in the ith sum
(C++17)
transform_exclusive_scan applies a functor, then calculates exclusive scan
(C++17)