Lunar

void cyclical(long offset, char GanZhi[5]) {
    long i = offset % 60;
    if (i < 0)
        i += 60;
    strcpy(GanZhi, Gan[i%10]);
    strcat(GanZhi, Zhi[i%12]);
}

void Lunar(int year, int month, int day, MyDate & dateOut)
{
 int i;
 int run=0, ping=0; // 閏年和平年個數
    long temp;
 long sum;

    // 公曆1900.1.31爲農曆的 乙亥年 戊寅月 甲辰日 正月初一
    dateOut.monCyl = 14; // 戊寅月
    dateOut.dayCyl = 40; // 甲辰日

    if ( year>1900 || year==1900 && (month>1 || day==31) )
    {
        // 計算當前時間 和 1900.1.31 之間的天數差
        for(i=1900; i<year; i++)
        {
            if(isleap(i))
                run++;
            else
                ping++;
        }
        // 計算總天數
        sum = 366*run + 365*ping;
        for(i=1; i<month; i++)
            sum += MonthDays(year, i);
        sum += day;
        sum -= 31;
        dateOut.dayCyl += sum;
       
        for(i=1900; i<TotalYear && sum>0; i++)
        {
            temp = lYearDays(i);
            sum -= temp;
            dateOut.monCyl += 12;
        }
       
        if(sum<0)
        {
            sum += temp;
            i--;
            dateOut.monCyl -= 12;
        }
        dateOut.year = i;
    }
    else // 1900.1.31日之前的公曆日期
    {
        // 計算當前時間 和 1900.1.31 之間的天數差
        if (year==1900) {
            sum = 31-day;
        }
        else
        {
            for(i=1899; i>year; --i)
            {
                if(isleap(i))
                    run++;
                else
                    ping++;
            }
            // 計算總天數
            sum = 366*run + 365*ping;
            for(i=month+1; i<13; ++i)
                sum += MonthDays(year, i);
            sum += MonthDays(year, month) - day;
            sum +=31;
        }

        dateOut.dayCyl -= sum;

        for(i=1899; i>=baseYear && sum>0; i--) {
            sum -= lYearDays(i);
            dateOut.monCyl -= 12;
        }

        if (sum<0)  // 此處，如果sum 大於 0， 則出錯，超出農曆年的範圍
            sum = -sum;
        dateOut.year = i+1;
    }

    int leap = leapMonth(dateOut.year); // 閏哪個月
    for (i=1; i<13; ++i)
    {
        temp = monthDays(dateOut.year, i);
        if (sum >= temp)
            sum -= temp;
        else
        {
            dateOut.month = i;
            dateOut.day = sum + 1;
            dateOut.isLeap = false;
            break;
        }

        if (i == leap) // 閏月
        {
            temp = leapDays(dateOut.year);
            if (sum >= temp)
                sum -= temp;
            else
            {
                dateOut.month = i;
                dateOut.day = sum + 1;
                dateOut.isLeap = true;
                break;
            }
        }
        dateOut.monCyl ++;
    }
}