std::ranges::set_symmetric_difference, std::ranges::set_symmetric_difference_result

Since C++20

Header: <algorithm>

Computes symmetric difference of two sorted ranges: the elements that are found in either of the ranges, but not in both of them are copied to the range beginning at result. The resulting range is also sorted.

# Declarations

Call signature

template< std::input_iterator I1, std::sentinel_for<I1> S1,
std::input_iterator I2, std::sentinel_for<I2> S2,
std::weakly_incrementable O, class Comp = ranges::less,
class Proj1 = std::identity, class Proj2 = std::identity >
requires std::mergeable<I1, I2, O, Comp, Proj1, Proj2>
constexpr set_symmetric_difference_result<I1, I2, O>
set_symmetric_difference( I1 first1, S1 last1, I2 first2, S2 last2,
O result, Comp comp = {},
Proj1 proj1 = {}, Proj2 proj2 = {} );

(since C++20)

template< ranges::input_range R1, ranges::input_range R2,
std::weakly_incrementable O, class Comp = ranges::less,
class Proj1 = std::identity, class Proj2 = std::identity >
requires std::mergeable<ranges::iterator_t<R1>, ranges::iterator_t<R2>,
O, Comp, Proj1, Proj2>
constexpr set_symmetric_difference_result<ranges::borrowed_iterator_t<R1>,
ranges::borrowed_iterator_t<R2>, O>
set_symmetric_difference( R1&& r1, R2&& r2, O result, Comp comp = {},
Proj1 proj1 = {}, Proj2 proj2 = {} );

(since C++20)

Helper types

template< class I1, class I2, class O >
using set_symmetric_difference_result = ranges::in_in_out_result<I1, I2, O>;

(since C++20)

# Parameters

# Return value

{last1, last2, result_last}, where result_last is the end of the constructed range.

# Example

#include <algorithm>
#include <iostream>
#include <iterator>
#include <vector>
 
void visualize_this(const auto& v, int min = 1, int max = 9)
{
    for (auto i {min}; i <= max; ++i)
    {
        std::ranges::binary_search(v, i) ? std::cout << i : std::cout << '.';
        std::cout << ' ';
    }
    std::cout << '\n';
}
 
int main()
{
    const auto in1 = {1, 3, 4,    6, 7, 9};
    const auto in2 = {1,    4, 5, 6,    9};
 
    std::vector<int> out {};
 
    std::ranges::set_symmetric_difference(in1, in2, std::back_inserter(out));
 
    visualize_this(in1);
    visualize_this(in2);
    visualize_this(out);
}

# See also