【转】阴历算法

//保存一个农历日期

typedef struct date_t
{
	int year;
	int month;
	int day;
	int leap;			//是否闰月
} date_t;

//公历转农历

date_t luanr_date(int solar_year,int solar_month,int solar_day);

#include <ctime>

//使用比特位记录每年的情况
//0~4 共5bit 春节日份
//5~6 共2bit 春节月份
//7~19 共13bit 13个月的大小月情况(如果无闰月，最后位无效)，大月为1,小月为0
//20~23 共4bit 记录闰月的月份，如果没有闰月为0

#define BEGIN_YEAR			1901
#define NUMBER_YEAR			199

int lunar_years[199] = {

	0x04AE53,0x0A5748,0x5526BD,0x0D2650,0x0D9544,
	0x46AAB9,0x056A4D,0x09AD42,0x24AEB6,0x04AE4A, //1901-1910

	0x6A4DBE,0x0A4D52,0x0D2546,0x5D52BA,0x0B544E,
	0x0D6A43,0x296D37,0x095B4B,0x749BC1,0x049754, //1911-1920

	0x0A4B48,0x5B25BC,0x06A550,0x06D445,0x4ADAB8,
	0x02B64D,0x095742,0x2497B7,0x04974A,0x664B3E, //1921-1930

	0x0D4A51,0x0EA546,0x56D4BA,0x05AD4E,0x02B644,
	0x393738,0x092E4B,0x7C96BF,0x0C9553,0x0D4A48, //1931-1940

	0x6DA53B,0x0B554F,0x056A45,0x4AADB9,0x025D4D,
	0x092D42,0x2C95B6,0x0A954A,0x7B4ABD,0x06CA51, //1941-1950

	0x0B5546,0x555ABB,0x04DA4E,0x0A5B43,0x352BB8,
	0x052B4C,0x8A953F,0x0E9552,0x06AA48,0x7AD53C, //1951-1960

	0x0AB54F,0x04B645,0x4A5739,0x0A574D,0x052642,
	0x3E9335,0x0D9549,0x75AABE,0x056A51,0x096D46, //1961-1970

	0x54AEBB,0x04AD4F,0x0A4D43,0x4D26B7,0x0D254B,
	0x8D52BF,0x0B5452,0x0B6A47,0x696D3C,0x095B50, //1971-1980

	0x049B45,0x4A4BB9,0x0A4B4D,0xAB25C2,0x06A554,
	0x06D449,0x6ADA3D,0x0AB651,0x093746,0x5497BB, //1981-1990

	0x04974F,0x064B44,0x36A537,0x0EA54A,0x86B2BF,
	0x05AC53,0x0AB647,0x5936BC,0x092E50,0x0C9645, //1991-2000

	0x4D4AB8,0x0D4A4C,0x0DA541,0x25AAB6,0x056A49,
	0x7AADBD,0x025D52,0x092D47,0x5C95BA,0x0A954E, //2001-2010

	0x0B4A43,0x4B5537,0x0AD54A,0x955ABF,0x04BA53,
	0x0A5B48,0x652BBC,0x052B50,0x0A9345,0x474AB9, //2011-2020

	0x06AA4C,0x0AD541,0x24DAB6,0x04B64A,0x69573D,
	0x0A4E51,0x0D2646,0x5E933A,0x0D534D,0x05AA43, //2021-2030

	0x36B537,0x096D4B,0xB4AEBF,0x04AD53,0x0A4D48,
	0x6D25BC,0x0D254F,0x0D5244,0x5DAA38,0x0B5A4C, //2031-2040

	0x056D41,0x24ADB6,0x049B4A,0x7A4BBE,0x0A4B51,
	0x0AA546,0x5B52BA,0x06D24E,0x0ADA42,0x355B37, //2041-2050

	0x09374B,0x8497C1,0x049753,0x064B48,0x66A53C,
	0x0EA54F,0x06B244,0x4AB638,0x0AAE4C,0x092E42, //2051-2060

	0x3C9735,0x0C9649,0x7D4ABD,0x0D4A51,0x0DA545,
	0x55AABA,0x056A4E,0x0A6D43,0x452EB7,0x052D4B, //2061-2070

	0x8A95BF,0x0A9553,0x0B4A47,0x6B553B,0x0AD54F,
	0x055A45,0x4A5D38,0x0A5B4C,0x052B42,0x3A93B6, //2071-2080

	0x069349,0x7729BD,0x06AA51,0x0AD546,0x54DABA,
	0x04B64E,0x0A5743,0x452738,0x0D264A,0x8E933E, //2081-2090

	0x0D5252,0x0DAA47,0x66B53B,0x056D4F,0x04AE45,
	0x4A4EB9,0x0A4D4C,0x0D1541,0x2D92B5 //2091-2099

};
//计算这个公历日期是一年中的第几天

static int day_of_solar_year(int year, int month, int day )
{
	//为了提高效率，记录每月一日是一年中的第几天
	int normal_yday[12] = {1, 32, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335};
	//闰年的情况
	int leap_yday[12] = {1, 32, 61, 92, 122, 153, 183, 214, 245, 275, 306, 336};
	const int *arr = normal_yday;

	//判断是否是公历闰年

	if(year % 4 == 0) {
		if(year % 100 != 0)    
			arr = leap_yday;
		if(year%400 == 0)
			arr = leap_yday;              
	}
	return arr[month -1] + (day -1);
}

date_t luanr_date(int solar_year, int solar_month, int solar_day)
{
	date_t luanr_date;

	luanr_date.year		= solar_year;
	luanr_date.month	= 0;
	luanr_date.day		= 0;
	luanr_date.leap		= 0;

	//越界检查，如果越界，返回无效日期

	if(solar_year <= BEGIN_YEAR || solar_year > BEGIN_YEAR + NUMBER_YEAR - 1)
		return luanr_date;

	int year_index = solar_year - BEGIN_YEAR;

	//计算春节的公历日期
	int spring_ny_month = ( lunar_years[year_index] & 0x60 ) >> 5;
	int spring_ny_day = ( lunar_years[year_index] & 0x1f);

	//计算今天是公历年的第几天
	int today_solar_yd = day_of_solar_year(solar_year, solar_month, solar_day);
	//计算春节是公历年的第几天
	int spring_ny_yd = day_of_solar_year(solar_year, spring_ny_month, spring_ny_day);
	//计算今天是农历年的第几天

	int today_luanr_yd = today_solar_yd - spring_ny_yd + 1;
	//如果今天在春节的前面，重新计算today_luanr_yd

	if(today_luanr_yd < 0) {
		//农历年比当前公历年小1
		year_index --;
		luanr_date.year --;
		//越界，返回无效日期
		if(year_index <0) return luanr_date;
		spring_ny_month = ( lunar_years[year_index] & 0x60 ) >> 5;
		spring_ny_day = ( lunar_years[year_index] & 0x1f);    
		spring_ny_yd = day_of_solar_year(solar_year, spring_ny_month, spring_ny_day);

		int year_total_day = day_of_solar_year(luanr_date.year, 12, 31);         
		today_luanr_yd = today_solar_yd + year_total_day - spring_ny_yd + 1;    
	}

	int luanr_month = 1;
	//计算月份和日期

	for(;luanr_month <= 13; luanr_month++) {    
		int month_day = 29;    
		if((lunar_years[year_index] >> (6 + luanr_month)) & 0x1)
			month_day = 30;    
		if(today_luanr_yd <= month_day ) break;
		else today_luanr_yd -= month_day;    
	}
	luanr_date.day = today_luanr_yd;
	//处理闰月
	int leap_month = (lunar_years[year_index] >>20) & 0xf;
	if(leap_month > 0 && leap_month < luanr_month )
	{    
		luanr_month --;
		//如果当前月为闰月，设置闰月标志

		if( luanr_month == leap_month )    
			luanr_date.leap = 1;         
	}
	//assert(leap_month <= 12);
	luanr_date.month = luanr_month;
	return luanr_date;
}


#include <iostream>
#include <ctime>



int main(int argc, char *argv[])
{
	using namespace std;

	time_t current_time;
	time(&current_time);
	tm *current_tm = localtime(&current_time);

	int year = current_tm->tm_year + 1900;
	int month = current_tm->tm_mon +1;
	int day = current_tm->tm_mday;

	date_t lunar_date = luanr_date(year, month, day);

	cout << lunar_date.year << "年";
	if(lunar_date.leap)
		cout << "闰";
	cout << lunar_date.month<<"月";
	cout << lunar_date.day<<"日";
	cout << endl;




	int iii;
	cin >> iii; 
	return 0;
}