写了一个时间处理的类，能将人类时间转换成距离公元零年一月一日秒数（时间戳），同时支持时间戳转换成日期时间

#include "stdafx.h"
#include <stdlib.h>
#include <string.h>
#include <time.h>

#define IS_LEAP_YEAR(y)  (((y) % 4 == 0 && (y) % 100 != 0) || (y) % 400 == 0)

#define if_not_eual_ret(left, right) do {\
    if (left < right) {return true;} else if(left > right) {return false;}\
    } while(0)

//从网上抄的 计算日期相差天数的函数
int day_diff(int year_start, int month_start, int day_start, 
    int year_end, int month_end, int day_end)
{
    int y2, m2, d2;
    int y1, m1, d1;

    m1 = (month_start + 9) % 12;
    y1 = year_start - m1/10;
    d1 = 365*y1 + y1/4 - y1/100 + y1/400 + (m1*306 + 5)/10 + (day_start - 1);

    m2 = (month_end + 9) % 12;
    y2 = year_end - m2/10;
    d2 = 365*y2 + y2/4 - y2/100 + y2/400 + (m2*306 + 5)/10 + (day_end - 1);

    return (d2 - d1);
}


class CMyDateTime
{
public:
    CMyDateTime(int sec_from_beg = 0)
    {
        m_sec_from_beg = sec_from_beg;
    }

    CMyDateTime(int year, int month, int day, int hour, int minute, int second)
    {
        m_sec_from_beg = to_second(year, month, day, hour, minute, second);
    }

    bool operator < (const CMyDateTime& theDate)
    {
        return m_sec_from_beg < theDate.m_sec_from_beg;
    }

    //获得0001 01:01:00至当前时间秒数
    long long to_second()
    {
        return m_sec_from_beg;
    }

    
    //年 取1900-3000 月 取0-11 日 取1-31 时分秒 取0-59
    static long long to_second(int year, int month, int day, int hour, int minute, int second)
    {
        //获取当前日期至纪元1年的天数
        int y1 = year, m1 = 0, d1 = day - 1;
        long long sec;

        //每月天数
        int month_day[] = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};

        if (IS_LEAP_YEAR(year))
        {
            month_day[1]++;
        }
        for (int i = 0; i < month; i++)
        {
            m1 += month_day[i];
        }

        y1 -= 1;
        d1 = 365*y1 + y1/4 - y1/100 + y1/400 + m1 + d1;

        //24小时 60分 60秒
        sec = (long long)d1 * (24 * 60 * 60);
        sec += hour * 3600 + minute * 60 + second;
        return sec;
    }

    //把秒数转换成标准日期
    bool to_date(int& year, int& month, int& day, int& hour, int& minute, int& second)
    {
        // 先计算大概年份，用秒数除以366天秒数
        int day_from_beg = (int)(m_sec_from_beg / (24 * 60 * 60));

        int second_left = int(m_sec_from_beg - day_from_beg * (long long) (24 * 60 * 60));
        hour = second_left / (60 * 60);

        second_left = int (second_left - hour * (60 * 60));
        minute = second_left / 60;
        second = second_left % 60;

        int year_cnt = day_from_beg / 366;
        //每年365天 闰年多一天
        int day_from_beg_to_year = (year_cnt * 365 + year_cnt / 4 - year_cnt / 100 + year_cnt / 400);

        //然后逐年累加天数，直到天数大于day_from_beg
        while (day_from_beg_to_year <= day_from_beg)
        {
            if (IS_LEAP_YEAR(year_cnt + 1))
            {
                day_from_beg_to_year += 366;
            }
            else
            {
                day_from_beg_to_year += 365;
            }
            year_cnt++;
        }
        //因为是要取最后一个小于等于在数 所以在这里要减一
        year_cnt--;

        //知道年份后，再计算月份 先计算出当前日期距离今年开始相差多少天
        int day_from_year = day_from_beg - (year_cnt * 365 + year_cnt / 4 - year_cnt / 100 + year_cnt / 400);
        //今年的年数 = 经过的年数 + 1
        year = year_cnt + 1;

        //每月天数
        int month_day[] = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};

        if (IS_LEAP_YEAR(year))
        {
            month_day[1]++;
        }

        for (month = 0; month < 12; month++)
        {
            if ((day_from_year - month_day[month]) < 0)
            {
                break;
            }

            day_from_year -= month_day[month];
        }
        day = day_from_year + 1;
        return true;
    }
private:
    //当前日期至纪元1年的秒数
    long long m_sec_from_beg;
};

//测试函数，测试每一秒钟从人类日期格式转换成CMyDateTime 再转换回来是否正确
void test_time()
{
    int month_day[] = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};

    for (int year = 1; year < 2100; year++)
    {
        double start = GetTickCount();
        bool is_leap = IS_LEAP_YEAR(year);
        if (is_leap)
        {
            month_day[1] = 29;
        }

        for (int month = 0; month < 12; month++)
        {
            for (int day = 1; day <= month_day[month]; day++)
            {
                for (int hour = 0; hour < 24; hour++)
                {
                    for (int minute = 0; minute < 60; minute++)
                    {
                        for (int second = 0; second < 60; second++)
                        {
                            CMyDateTime t(year, month, day, hour, minute, second);
                            int year_new, month_new, day_new, hour_new, minute_new, second_new;
                            if (t.to_date(year_new, month_new, day_new, hour_new, minute_new, second_new))
                            {
                                if (year != year_new || month != month_new || day_new != day ||
                                    hour != hour_new || minute != minute_new || second != second_new)
                                {
                                    printf("day = %d day_new = %d\n", day, day_new);
                                    printf("month = %d month_new = %d\n", month, month_new);
                                    printf("year = %d year_new = %d\n", year, year_new);


                                    printf("hour = %d hour_new = %d\n", hour, hour_new);
                                    printf("minute = %d minute_new = %d\n", minute, minute_new);
                                    printf("second = %d second_new = %d\n", second, second_new);
                                    printf("------------------------\n");
                                }
                            }
                        }
                    }
                }
            }
        }

        if (is_leap)
        {
            month_day[1] = 28;
        }

        //我的机器一年花5秒左右 效率不是特别高 但目前没有优化头绪
        printf("总共耗时 %f 毫秒\n", GetTickCount() - start);
        printf("------------[%04d]------------\n", year);
    }
}