Doomsday rule: Difference between revisions
Added Wren
(Added Wren) |
|||
Line 113:
February 12, 2077 will be on a Friday
April 2, 2101 will be on a Saturday
</pre>
=={{header|Wren}}==
{{libheader|Wren-date}}
We only use the above module to check the dates of the week given by Conway's method. The latter are worked out from scratch.
<lang ecmascript>import "/date" for Date
var days = ["Sunday", "Monday", "Tuesday", "Wednesday","Thursday", "Friday", "Saturday"]
var anchorDay = Fn.new { |y| (2 + 5 * (y%4) + 4 *(y%100) + 6 * (y%400)) % 7 }
var isLeapYear = Fn.new { |y| y%4 == 0 && (y%100 != 0 || y%400 == 0) }
var firstDaysCommon = [3, 7, 7, 4, 2, 6, 4, 1, 5, 3, 7, 5]
var firstDaysLeap = [4, 1, 7, 4, 2, 6, 4, 1, 5, 3, 7, 5]
var dates = [
"1800-01-06",
"1875-03-29",
"1915-12-07",
"1970-12-23",
"2043-05-14",
"2077-02-12",
"2101-04-02"
]
System.print("Days of week given by Doomsday rule:")
for (date in dates) {
var y = Num.fromString(date[0..3])
var m = Num.fromString(date[5..6]) - 1
var d = Num.fromString(date[8..9])
var a = anchorDay.call(y)
var w = d - (isLeapYear.call(y) ? firstDaysLeap[m] : firstDaysCommon[m])
if (w < 0) w = 7 + w
var dow = (a + w) % 7
System.print("%(date) -> %(days[dow])")
}
System.print("\nDays of week given by Date module:")
for (date in dates) {
var d = Date.parse(date, Date.isoDate)
System.print("%(date) -> %(d.weekDay)")
}</lang>
{{out}}
<pre>
Days of week given by Doomsday rule:
1800-01-06 -> Monday
1875-03-29 -> Monday
1915-12-07 -> Tuesday
1970-12-23 -> Wednesday
2043-05-14 -> Thursday
2077-02-12 -> Friday
2101-04-02 -> Saturday
Days of week given by Date module:
1800-01-06 -> Monday
1875-03-29 -> Monday
1915-12-07 -> Tuesday
1970-12-23 -> Wednesday
2043-05-14 -> Thursday
2077-02-12 -> Friday
2101-04-02 -> Saturday
</pre>
| |||