PV913ArreyMegaExampleSTL

#include <iostream>
#include <vector>
#include <algorithm>

template <class InIter>
InIter dup_only(InIter begin, InIter end)
{
    InIter out{ begin };
    while (begin != end and std::next(begin) != end)
    {
        if (*begin == *std::next(begin))
            *out++ = std::move(*begin++);
        if (begin != end)
            ++begin;
    }
    return out;
}

template <class InIter>
InIter dedup(InIter begin, InIter end)
{
    InIter out{ begin };
    while (begin != end and std::next(begin) != end)
    {
        if (*begin != *std::next(begin))
            *out++ = std::move(*begin++);
        else
            if (++begin != end)
                ++begin;
    }
    if (begin != end)
        *out++ = std::move(*begin);
    return out;
}

int main()
{
    char input{ 'x' };
    std::vector<int> arrA{ 6,1,4,2,8,9,11,26,2,7,8,11,2,2,3 };
    std::vector<int> arrB{ 1,8,29,2,2,9,11,1,2,5,8,34,12,9,8 };

    std::sort(arrA.begin(), arrA.end());
    std::sort(arrB.begin(), arrB.end());

    std::copy(arrA.begin(), arrA.end(), std::ostream_iterator<int>(std::cout, " ")); std::cout << '\n';
    std::copy(arrB.begin(), arrB.end(), std::ostream_iterator<int>(std::cout, " ")); std::cout << '\n';
    std::cout << '\n';

    auto aUnique{ std::unique(arrA.begin(), arrA.end()) };
    auto bUnique{ std::unique(arrB.begin(), arrB.end()) };

    std::copy(arrA.begin(), aUnique, std::ostream_iterator<int>(std::cout, " ")); std::cout << '\n';
    std::copy(arrB.begin(), bUnique, std::ostream_iterator<int>(std::cout, " ")); std::cout << '\n';
    std::cout << '\n';

    do
    {
        std::cout << "\na - Only different elements from A and B without duplicates\n";
        std::cout << "b - Only common elements from A and B without duplicates\n";
        std::cout << "c - Only elements from A that not in B without duplicates\n";
        std::cout << "d - Only elements from B that not in A without duplicates\n";
        std::cin >> input; input = tolower(input);
        std::cout << '\n';
        if (input == 'a')
        {
            std::vector<int> res(std::distance(arrA.begin(), aUnique) + std::distance(arrB.begin(), bUnique));
            std::merge(arrA.begin(), aUnique, arrB.begin(), bUnique, res.begin());
            std::copy(res.begin(), res.end(), std::ostream_iterator<int>(std::cout, " ")); std::cout << '\n';
            std::cout << '\n';
            auto resEnd{ dedup(res.begin(), res.end()) };
            std::copy(res.begin(), resEnd, std::ostream_iterator<int>(std::cout, " ")); std::cout << '\n';
        }
        else if (input == 'b')
        {
            std::vector<int> res(std::distance(arrA.begin(), aUnique) + std::distance(arrB.begin(), bUnique));
            std::merge(arrA.begin(), aUnique, arrB.begin(), bUnique, res.begin());
            std::copy(res.begin(), res.end(), std::ostream_iterator<int>(std::cout, " ")); std::cout << '\n';
            std::cout << '\n';
            auto resEnd{ dup_only(res.begin(), res.end()) };
            std::copy(res.begin(), resEnd, std::ostream_iterator<int>(std::cout, " ")); std::cout << '\n';
        }
        else if (input == 'c')
        {
            auto aEnd{ std::copy_if(arrA.begin(), aUnique, arrA.begin(),
            [&arrB](const auto& el) { return !(std::binary_search(arrB.begin(), arrB.end(), el)); }) };

            std::copy(arrA.begin(), aEnd, std::ostream_iterator<int>(std::cout, " "));
            std::cout << '\n';
        }
        else if (input == 'd')
        {
            auto bEnd{ std::copy_if(arrB.begin(), bUnique, arrB.begin(),
            [&arrA](const auto& el) { return !(std::binary_search(arrA.begin(), arrA.end(), el)); }) };

            std::copy(arrB.begin(), bEnd, std::ostream_iterator<int>(std::cout, " "));
            std::cout << '\n';
        }
    } while (input != 'x');
    return 0;
}