在我做那个天气时钟的时候，自己加了农历显示，但今年的春节的时候发现农历显示不正确，只有月份没有日期。我把相关代码做改成电脑运行后发现这个代码整个2021年农历显示都有问题。比如：
公历2021年2月11日应该是除夕，4月11日农历是2月30，这个问题我在查，另外我查了一下原码，发现一个我理解不了的问题：
原码使用一个16进制数表示一些信息，比如，2021年是如下的16进制数：
0X06D54C
转换为2进制为：000001101101010101001100
该24位的定义为：（如果我没理解错的话应该是按照下面规则分解，但直接计算结果是错的）
0~4 共5bit 春节日份，即：00000（10进制的0，感觉明显是错的。）
5~6 共2bit 春节月份，即：11（10进制的3，也是错的）
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，即：0110101010100
20~23 共4bit 记录闰月的月份，如果没有闰月为0，即：1100
更让人迷惑的事是下面的代码：
//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);
第一行明显示是取月份，但为什么与0x60与计算后再右移5位就得到了月份，这是为什么?
经我计算如下：0x60的二进制是：01100000与000001101101010101001100与计算后得到：000000000000000001000000，右移5位后得到10，即为十进制的2，是正确的。今年的春节是2月12日（初一为春节）
第二行，与0x1f与计算后得到农历日期。这又是为什么?
经计算得到1100，为10进制的12也是正确的。今年的春节是2月12日（初一为春节）
这两个计算的原理是什么?麻烦哪位大神可以告知，不胜感激。附上三个文件的原码。注意：原码计算农历日期是错的，我正在找原因，请勿使用!
//file: chdate.cpp
//author: [email protected]
//2007-02-13 11:21:45
#include <iostream>
#include <ctime>
#include "lunarday.h"
int main(int argc, char *argv[])
{
using namespace std;
using namespace lunar;
//time_t current_time;
//time(¤t_time);
//tm *current_tm = localtime(¤t_time);
//int year = current_tm->tm_year + 1900;
//int month = current_tm->tm_mon + 1;
//int day = current_tm->tm_mday;
int year=2021;
int month;
int day;
while (true){
//cout << "请输入年份：";
//cin >> year;
cout << "请输入月份：";
cin >> month;
cout << "请输入日期：";
cin >> day;
Date lunar_date = LuanrDate(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;
//return 0;
}
}
//lunarday.cpp
#include "lunarday.h"
#include <ctime>
#include <cassert>
#include <cstring>
#include <iostream>
using namespace std;
using lunar::Date;
//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
static const int BEGIN_YEAR = 1901;
static const int NUMBER_YEAR = 199;
static const unsigned 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
0X06D54C,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 DayOfSolarYear(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
static const int NORMAL_YDAY[12] = { 1,32,60,91,121,152,
182,213,244,274,305,335 };
//闰年的情况
static const int LEAP_YDAY[12] = { 1,32,61,92,122,153,
183,214,245,275,306,336 };
const int *t_year_yday_ = NORMAL_YDAY;
//判断是否是公历闰年
if (year % 4 == 0)
{
if (year % 100 != 0)
t_year_yday_ = LEAP_YDAY;
if (year % 400 == 0)
t_year_yday_ = LEAP_YDAY;
}
return t_year_yday_[month - 1] + (day - 1);
}
Date lunar::LuanrDate(int solar_year, int solar_month, int solar_day)
{
Date luanr_date;
luanr_date.year = solar_year;
luanr_date.month = 0;
luanr_date.day = 0;
luanr_date.leap = false;
//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 = DayOfSolarYear(solar_year, solar_month, solar_day);
//计算春节是公历年的第几天
int spring_ny_yd = DayOfSolarYear(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 = DayOfSolarYear(solar_year, spring_ny_month, spring_ny_day);
int year_total_day = DayOfSolarYear(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 = true;
}
assert(leap_month <= 12);
luanr_date.month = luanr_month;
return luanr_date;
}//lunarday.h
namespace lunar
{
//保存一个农历日期
typedef struct T_Date
{
//年
int year;
//月
int month;
//日
int day;
//是否闰月
bool leap;
} Date;
//公历转农历
Date LuanrDate(int solar_year, int solar_month, int solar_day);
}