PV913FunctionPtrFunctorsExplained

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

template <typename ElemType>
class Printer
{
    std::ostream& out;
    char delimiter;
public:
    Printer(std::ostream& outP, char delimiterP) : out{ outP }, delimiter{ delimiterP } {};
    Printer() :Printer{ std::cout, '\0' } {};
    Printer(char delimiterP) : Printer{ std::cout, delimiterP } {};
    void operator()(const ElemType& elem) const
    {
        out << elem;
        if (delimiter) out << delimiter;
    };
};

class Numerator
{
    int curr;
    int delta;
    static int sumCnt;
public:
    Numerator(int startP, int deltaP) : curr{ startP }, delta{ deltaP }{};
    Numerator() : Numerator{ 0,1 } {};
    int operator()()
    {
        ++sumCnt;
        int ret{ curr };
        curr += delta;
        return ret;
    }
    static int getSumCnt() { return sumCnt; };
};

int Numerator::sumCnt{ 0 };

template <typename T>
void prn(const T& obj)
{
    std::cout << obj << ' ';
}

template <typename Action>
void gen(int beg, int end, Action fun)
{
    while (beg++ != end)
    {
        std::cout << fun() << ' ';
    }
}

int main()
{
    Numerator n3{ 0,3 };
    Numerator n3_1{ 0,3 };

    for (int i{ 0 }; i < 5; ++i)
    {
        std::cout << n3() << ' ';
    }

    std::cout << '\n';

    gen(0, 5, n3_1);

    return 0;

    std::vector<int> arr(10);
    std::vector<int> arr1(20);
    std::list<char> symbols{ 'a','s','d','a','s','x','v' };

    Printer<int> printer{ ' ' };
    Printer<int> printerNl{ '\n' };

    /*std::for_each(arr.begin(), arr.end(),
        [](auto& el) { el = rand() % 10; std::cout << el << ' '; });*/

    int cnt{ 1 };
    int delta{ 2 };

    Numerator num{1,3};
    Numerator num2x2{ 2,2 };

    //std::generate(arr.begin(), arr.end(), [&]() { return cnt+=delta; });
    std::generate(arr.begin(), arr.end(), num);

    std::cout << '\n';
    std::for_each(arr.begin(), arr.end(), prn<int>);
    //std::copy(arr.begin(), arr.end(), std::ostream_iterator<int>(std::cout, " ")); std::cout << '\n';

    std::cout << '\n';

    std::generate(arr1.begin(), arr1.end(), num2x2);

    std::cout << '\n';
    std::copy(arr1.begin(), arr1.end(), std::ostream_iterator<int>(std::cout, " ")); std::cout << '\n';

    std::cout << "Totally Numerated elements: " << Numerator::getSumCnt() << '\n';




    /*auto it{ arr.begin() };

    while ((it = std::find(it, arr.end(), 1)) != arr.end())
    {
        std::cout << "res is: " << std::distance(arr.begin(), it) << " <=> " << *it << '\n';
        ++it;
    }*/
    //std::copy(arr.begin(), arr.end(), std::ostream_iterator<int>(std::cout, " ")); std::cout << '\n';
    //std::cout << '\n';

    //std::stable_partition(arr.begin(), arr.end(), [](int el) { return el % 2; });

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

    //auto res{ std::find(arr.begin(), arr.end(), 0)};
    //auto res{ std::count_if(arr.begin(), arr.end(),[](int el) { return (el % 2 == 0) and (el > 5); }) };



    /*if (res != arr.end())
    {
        std::cout << "res is: " << std::distance(arr.begin(), res) << " <=> " << *res << '\n';
    }
    else
    {
        std::cout << "Not FOUND!!\n";
    }*/
    return 0;
}