Question

So I have an assignment where I’m supposed to code a Mayan calendar in C++, in such a manner that the calendar has these functions:

argv[1] | argv[2]        |  argv[3]        | output
m+d     | Mayan date     |  number of days | Mayan date
m-d     | Mayan date     |  number of days | Mayan date
m-m     | Mayan date     |  Mayan date     | number of days
g=      | Gregorian date |                 | Mayan date
m=      | Mayan date     |                 | Gregorian date

The first operation m+d takes a Mayan date and a number of days. The
operation adds the number of days to the Mayan date to produce a Mayan
date as output. The second operation m-d subtracts the number of days
from the Mayan date to produce a Mayan date as output. The third
operation m-m calculates the number of days between two Mayan dates.
The fourth operation g= converts a Gregorian date to a Mayan date.
The final operation m= converts a Mayan date to a Gregorian date.

The mayan calendar units are set up in such a manner that:

Days                  Long Count period         Long Count unit
1                                               1 Kin
20                    20 Kin                    1 Uinal
360                   18 Uinal                  1 Tun
7,200                 20 Tun                    1 Ka'tun
144,000               20 Ka'tun                 1 Bak'tun
2,880,000             20 Bak'tun                1 Pictun
57,600,000            20 Pictun                 1 Kalabtun
1,152,000,000         20 Kalabtun               1 K'inchiltun
23,040,000,000        20 K'inchiltun            1 Alautun

I’m having trouble initializing the Mayan calendar object. Here is what I have so far:

class MayanDate {
// Bak'tun, Ka'tun, etc stuff ...
unsigned int Kin = 1;
unsigned int Uinal = 20;
unsigned int Tun = 360;
unsigned int Katun = 7200;
unsigned int Baktun = 144000;
unsigned int Pictun = 2880000;
unsigned int Kalabtun = 57600000;
unsigned long Kinchiltun = 1152000000;
unsigned long Alautun = 23040000000;


public:

        MayanDate();
        MayanDate( unsigned int, unsigned int, unsigned int, unsigned int, unsigned int);

        void set( unsigned int, unsigned int, unsigned int, unsigned int, unsigned int);
        MayanDate &operator++();
        int operator-( const MayanDate &) const;
        MayanDate operator+( unsigned int ) const;
        MayanDate operator-( unsigned int) const;
        bool operator==( const MayanDate & ) const;
        bool operator!=(const MayanDate & m ) const;
        void get_string( char*, unsigned int) const;
};

I want to be able to set the units to equal the number of days they represent when I initialize the class, so it’ll be easier to work with them.

The code I have above isn’t compiling, and I can’t figure out why. Any pointers towards what I’m doing wrong would be extremely helpful.

Answer 1

I think you should hold data in your class in Mayan style. You must have an ability to convert days from start of Maya epoch to it, like that:

void toMayan(long long d)
{
  kin = d % 20; d /= 20;
  unial = d % 18; d /= 18;
  tun = d %20; d /= 20;
  //...
}

And back conversion is simple: kin + 20 * (unial + 18 * (tun + 20 * (...)))

Next, you should to know how calculate count of days in Gregorian calendar from some date to another. You can look at java’s Date class sources ( http://www.docjar.com/html/api/java/util/Date.java.html ) for example.

And the last – you must know any Mayan date in Gregorian form to calculate differecne in days between calendars. Convert one date to days, subtract(or add) difference and then convert to other.