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Talk:Holidays related to Easter: Difference between revisions
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: Apologies for the misinformation about Christmas (I think that was me; I was in any case under that same mistaken belief). But let's not refer to anyone's faith as "heresy" here, please. This is a programming site, not a place to get into a literal religious debate. I have edited the desciption text to be hopefully both more accurate and more balanced. --[[User:Markjreed|Markjreed]] ([[User talk:Markjreed|talk]]) 15:48, 8 March 2021 (UTC)
:: Ok, it looks good. I would like to draw your attention to the problem again. The description correctly says: "In the year 400 CE, Easter Sunday was April 1st", this is the date according to the calendar valid in the 400th year. However, in most solutions, the date is April 2, that is, Monday. I suppose that the solution to this task should be the following (I wrote the code in JS, but I think everyone understands it):
:: <lang javascript>function getEasterDate(year = new Date().getFullYear(), church = 1, calendar = year < 1918 ? 1 : 2) {
/* year: a number of the year (from 325 CE);
church: an algorithm of the computus,
for Orthodox = 1; for Catholic = 2;
calendar: a calendar of the output date,
Julian = 1; Gregorian = 2. */
if (church == 1) {
let d = (year % 19 * 19 + 15) % 30;
d += (year % 4 * 2 + year % 7 * 4 + 6 * d + 6) % 7;
if (calendar == 1)
return d > 9 ? [d - 9, 4] : [22 + d, 3];
else if (calendar == 2) {
const c = (year / 100 | 0) - (year / 400 | 0) - 2;
return d > 39 - c ? [d - 39 + c, 5] : [d - 9 + c, 4];
}
}
else if (church == 2) {
const
a = year % 19, b = year / 100 | 0, c = year % 100,
d = (19 * a + b - (b / 4 | 0) - ((b - ((b + 8) / 25 | 0) + 1) / 3 | 0) + 15) % 30,
e = (32 + 2 * (b % 4) + 2 * (c / 4 | 0) - d - c % 4) % 7,
f = d + e - 7 * ((a + 11 * d + 22 * e) / 451 | 0) + 114;
if (calendar == 1) {
const
g = f % 31 + 1,
h = (year / 100 | 0) - (year / 400 | 0) - 2;
return g <= h ? [31 + g - h, 3] : [g - h, f / 31 | 0];
}
else if (calendar == 2)
return [f % 31 + 1, f / 31 | 0];
}
}
const
OrthodoxHolidays = [["Easter", 1], ["Ascension", 40], ["Trinity (Pentecost)", 50], ["All Saints' Sunday", 57]],
CatholicHolidays = [["Easter", 1], ["Ascension", 40], ["Pentecost", 50], ["Trinity Sunday", 57], ["Corpus Christi", 61]];
const firstYearOfNewStyle = 1918;
function getHolidaysDates(year, church) {
let Easter = getEasterDate(year, church, year < firstYearOfNewStyle ? 1 : 2);
const holidays = church == 1 ? OrthodoxHolidays : CatholicHolidays;
return year + ": " +
holidays.map(h => {
let d = new Date(year, Easter[1] - 1, Easter[0]);
d.setDate(d.getDate() + h[1] - 1);
return h[0] + ": " + new Intl.DateTimeFormat("ru", { month: "numeric", day: "numeric" }).format(d);
}).join("; ") + ".";
}
document.write(getHolidaysDates(400, 1));</lang>
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