std::transform_inclusive_scan

Since C++17

Header: <numeric>

Computes the inclusive prefix sum using op.

# Declarations

template< class InputIt, class OutputIt,
class BinaryOp, class UnaryOp >
OutputIt transform_inclusive_scan
( InputIt first, InputIt last, OutputIt d_first,
BinaryOp binary_op, UnaryOp unary_op );

(since C++17) (constexpr since C++20)

template< class ExecutionPolicy,
class ForwardIt1, class ForwardIt2,
class BinaryOp, class UnaryOp >
ForwardIt2 transform_inclusive_scan
( ExecutionPolicy&& policy,
ForwardIt1 first, ForwardIt1 last, ForwardIt2 d_first,
BinaryOp binary_op, UnaryOp unary_op );

(since C++17)

template< class InputIt, class OutputIt,
class BinaryOp, class UnaryOp, class T >
OutputIt transform_inclusive_scan
( InputIt first, InputIt last, OutputIt d_first,
BinaryOp binary_op, UnaryOp unary_op, T init );

(since C++17) (constexpr since C++20)

template< class ExecutionPolicy,
class ForwardIt1, class ForwardIt2,
class BinaryOp, class UnaryOp, class T >
ForwardIt2 transform_inclusive_scan
( ExecutionPolicy&& policy,
ForwardIt1 first, ForwardIt1 last, ForwardIt2 d_first,
BinaryOp binary_op, UnaryOp unary_op, T init );

(since C++17)

# 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
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

# Return value

Iterator to the element past the last element written.

# Notes

unary_op is never applied to init.

The parameter init appears last, differing from std::transform_exclusive_scan, because it is optional for this function.

# Example

#include <functional>
#include <iostream>
#include <iterator>
#include <numeric>
#include <vector>
 
int main()
{
    std::vector data{3, 1, 4, 1, 5, 9, 2, 6};
 
    auto times_10 = [](int x) { return x * 10; };
 
    std::cout << "10 times exclusive sum: ";
    std::transform_exclusive_scan(data.begin(), data.end(),
                                  std::ostream_iterator<int>(std::cout, " "),
                                  0, std::plus<int>{}, times_10);
    std::cout << "\n10 times inclusive sum: ";
    std::transform_inclusive_scan(data.begin(), data.end(),
                                  std::ostream_iterator<int>(std::cout, " "),
                                  std::plus<int>{}, times_10);
    std::cout << '\n';
}