#include <iostream>
#include <chrono>
#include <ratio>
#include <vector>
#include <numeric>

template <class Rep, class Period = std::ratio<1> >
using tmp_t = std::chrono::duration<Rep, Period>;

typedef tmp_t<int64_t> dollar_t;
typedef tmp_t<int64_t, std::ratio<1,100>> cent_t;

typedef tmp_t<int64_t, std::ratio<1,100>> store_money_t;
typedef tmp_t<double> show_money_t;
dollar_t dollar_lost_cents_cast(cent_t cents) { return std::chrono::duration_cast<dollar_t>(cents); }
std::ostream& operator<<(std::ostream& os, show_money_t show_money) { os << "$" << show_money.count(); return os; }
std::ostream& operator<<(std::ostream& os, store_money_t store_money) { os << store_money.count(); return os; }

int main() {

	// example
	store_money_t store_money = dollar_t(2) + cent_t(20);
	store_money += dollar_t(7);
	store_money += cent_t(18);
	
	cent_t cents = store_money;
	dollar_t dollars = dollar_lost_cents_cast(cents);
	show_money_t show_money = cents;
	
	std::cout << "dollar_lost_cents_cast = " << dollar_lost_cents_cast(store_money).count() << 
		", store_money = " << store_money << 		
		", show_money = " << show_money << 
		std::endl;

	std::vector<store_money_t> user_accounts(1000, store_money);
	store_money_t total = std::accumulate (user_accounts.begin(), user_accounts.end(), store_money_t(0));
	std::cout << "total = " << show_money_t(total);

	return 0;
}

#include <iostream>
#include <chrono>
#include <ratio>
#include <vector>
#include <numeric>
#include <algorithm>

template <class Rep, class Period = std::ratio<1> >
using tmp_t = std::chrono::duration<Rep, Period>;

typedef tmp_t<int64_t> dollar_t;
typedef tmp_t<int64_t, std::ratio<1,100>> cent_t;

//typedef tmp_t<int64_t, std::ratio<1,100>> store_money_t;
struct store_money_t : cent_t { 
	store_money_t(cent_t::rep v = 0, bool null = false) : cent_t(v), is_null(null) {} 
	store_money_t(cent_t c) : cent_t(c) {} 
	store_money_t(dollar_t d) : cent_t(d) {} 
	bool is_null = false;
};

dollar_t dollar_lost_cents_cast(cent_t cents) { return std::chrono::duration_cast<dollar_t>(cents); }
std::ostream& operator<<(std::ostream& os, store_money_t store_money) { 
	os << store_money.count()/100 << "." << store_money.count()%100; 
	return os; 
}

store_money_t null_money(0, true);
bool not_null_money(store_money_t &m) { return !m.is_null; }

int main() {

	// example
	store_money_t store_money = dollar_t(2) + cent_t(20);
	store_money += dollar_t(7);
	store_money += cent_t(18);
	
	cent_t cents = store_money;
	dollar_t dollars = dollar_lost_cents_cast(cents);
	
	std::cout << "dollar_lost_cents_cast = " << dollar_lost_cents_cast(store_money).count() << 
		", store_money = " << store_money << std::endl;

	// INSERT INTO Table ( Column1 ) VALUES ( 0), ( null ), ( 6 )
	// SELECT AVG( Column1 ) FROM Table
	std::vector<store_money_t> user_accounts = { cent_t(0), null_money, dollar_t(6) };

	store_money_t sum = std::accumulate (user_accounts.begin(), user_accounts.end(), store_money_t());
	std::cout << "sum = " << sum << std::endl;
	
	store_money_t::rep count = std::count_if(user_accounts.begin(), user_accounts.end(), not_null_money);
	std::cout << "count = " << count << std::endl;
	
	store_money_t avg = sum / count;
	std::cout << "avg = " << avg << std::endl;
	
	// SELECT 0 + null + 6 FROM dual
	store_money_t sum_select_statment = cent_t(0) + null_money + dollar_t(6);
	std::cout << "sum_select_statment = " << sum_select_statment << std::endl;
	
	return 0;
}

int main() {
  qty_t amount = 20.32, 
  price_t price = 100.321, 
  money_t sum;

  sum = price * amount; // 2038.50 в итоге, half up round to 2 magic
}