C++通过boost.date_time进行时间运算

ptime now = second_clock::local_time();
cout << now << endl;

cout << now.date().day_of_week();

ptime today = now - now.time_of_day();
ptime next_time = now + years(1) + months(1) + days(1) - hours(1);

time_duration timespan = now - today;

bool result = next_day > now;

cout << time_from_string("2010-09-10 10:01:01");

ptime time_parse_exact(const string& time_str, const string& format)
{
    ptime output;
    time_input_facet facet1(format, 1);

    std::stringstream ss1(time_str);
    ss1.imbue(std::locale(ss1.getloc(), &facet1));
    ss1 >> output;

    return output;
}
cout << time_parse_exact("2010/09/10-10:01:01", "%Y/%m/%d-%H:%M:%S");

#include <boost/timer/timer.hpp>
int main(void)
{
    boost::timer::cpu_timer timer;
    for (long i = 0; i < 100000000; ++i)
        std::sqrt(123.456L);

    cout << timer.format() << endl;
    //std::cout << timer.format(5, "%ws wall time,%ts totle time\n");

    return 0;
}