Function to return date of Easter for the given year

Question

So, here\'s a funny little programming challenge. I was writing a quick method to determine all the market holidays for a particular year, and then I started reading about E

Answer 1

When it came for me to write this (traffic prediction based on day of week and holiday), I gave up on trying to write it by myself. I found it somewhere on the net. The code was public domain, but...

sigh

see for yourself.

void dateOfEaster(struct tm* p)
{
    int Y = p->tm_year;
    int a = Y % 19;
    int b = Y / 100;
    int c = Y % 100;
    int d = b / 4;
    int e = b % 4;
    int f = (b + 8) / 25;
    int g = (b - f + 1) / 3;
    int h = (19 * a + b - d - g + 15) % 30;
    int i = c / 4;
    int k = c % 4;
    int L = (32 + 2 * e + 2 * i - h - k) % 7;
    int m = (a + 11 * h + 22 * L) / 451;
    p->tm_mon = ((h + L - 7 * m + 114) / 31 ) - 1;
    p->tm_mday = ((h + L - 7 * m + 114) % 31) + 1;
    p->tm_hour = 12;
    const time_t tmp = mktime(p);
    *p = *localtime(&tmp);  //recover yday from mon+mday
}

Some questions are better left unasked.

I feel lucky that all moving holidays in my country are a fixed offset from the date of Easter.