Thread: Easter Sunday

Hi,

I'm tasked with creating a program that displays the date of Easter Sunday, and this is what I have been able to do far:

Code:

#include <stdio.h>

int year, c, d, e, a, b, result, day, month;

int main() {
    year = 2013;
    c = year % 19;
    d = year % 4;
    e = year % 7;
    a = (19 * c + 24) % 30;
    b = (2 * d + 4 * e + 6 * a + 5) % 7;
    result = 22 + a + b;
    day = result % 30 + ?; // ???
    month = 3 + ?; // ???
    printf("Easter Sunday in year %d is day %d of month %d\n", year, day, month);
}

What I'm stuck on is displaying the day and month correctly. Apparently we have to add a "magic quantity".

Easter Sunday is celebrated on the Sunday following the paschal full moon: a full moon on or following the spring equinox. The church uses some approximations to make the calculation uniform: the lunar calendar begins with the new moon of the month of March and the full moon falls 14 days after. That should explain why Easter is on the 31 day this year for many denominations.

The Eastern Orthodox church still uses the Julian calendar so the day is different for them.

The church uses a few tables to help them calculate Easter for a given year, so saying "a magic quantity" really leaves me wondering what quantity you might be referring to, but I will link resources in the hope that you find or reckon what you need.

Easter Dating Method - Calculate the Date of Easter Sunday
How Is the Date of Easter Calculated? - How Do Christians Calculate the Date of Easter?

From what we have been told in the class the magic quantity is the thing that yields a 0 for any March result and a 1 for any April result.

We are then given the example: result/32

Not exactly sure how to code this.

Here is my latest code:
I seem to have sorted out the months. Cant seem to get Days to display correctly.

Code:

#include <stdio.h>

int year, c, d, e, a, b, result, day, month;

int main() {
    year = 2013;
    c = year % 19;
    d = year % 4;
    e = year % 7;
    a = (19 * c + 24) % 30;
    b = (2 * d + 4 * e + 6 * a + 5) % 7;
    result = 22 + a + b;
    day = result % 32 + 2;
    month = 3 + result / 31;
    printf("Easter Sunday in year %d is day %d of month %d\n", year, day, month);
}