Show the epoch
You are encouraged to solve this task according to the task description, using any language you may know.
Choose popular date libraries used by your language and show the epoch those libraries use. A demonstration is preferable (e.g. setting the internal representation of the date to 0 ms/ns/etc., or another way that will still show the epoch even if it is changed behind the scenes by the implementers), but text from (with links to) documentation is also acceptable where a demonstration is impossible/impractical. For consistency's sake, show the date in UTC time where possible.
See also: Date format
C
<lang c>#include <time.h>
- include <stdio.h>
int main() {
time_t t = 0;
printf("%s", asctime(gmtime(&t)));
return 0;
}</lang>
Output:
Thu Jan 1 00:00:00 1970
Go
<lang go>package main import ("fmt"; "time")
func main() {
fmt.Println(time.SecondsToUTC(0))
}</lang>
Output:
Thu Jan 1 00:00:00 UTC 1970
Icon and Unicon
Date and Time can be accessed via a number of keywords and functions
- The following are available in both Icon and Unicon
- &clock, &date, &dateline, and &time deal with current times and dates
- The following are specific to Unicon
- &now provides the number of seconds since the epoch, Jan 1, 1970 00:00:00
- ctime(integer) takes the number of seconds since the epoch and returns the date and time as a string in the local timezone
- gtime(integer) takes the number of seconds since the epoch and returns the date and time as a string in UTC
- gettimeofday() returns a record with the current time since the epoch in seconds and microseconds
- datetime routines use a global variable 'DateBaseYear' which defaults to Jan 1, 1970 00:00:00 but can be set if desired.
- The example below uses only a couple of the datetime procedures
<lang Unicon>link printf,datetime
procedure main()
# Unicon
now := gettimeofday().sec
if now = &now then printf("&now and gettimeofday().sec are equal\n")
printf("Now (UTC) %s, (local) %s\n",gtime(now),ctime(now))
printf("Epoch %s\n",gtime(0))
# Icon and Unicon
now := DateToSec(&date) + ClockToSec(&clock)
printf("Now is also %s and %s\n",SecToDate(now),SecToDateLine(now))
end</lang>
Sample Output:
&now and gettimeofday().sec are equal Now (UTC) Tue Aug 09 10:43:23 2011, (local) Tue Aug 09 06:43:23 2011 Epoch Thu Jan 01 00:00:00 1970 Now is also 2011/08/09 and Tuesday, August 9, 2011 6:43 am
J
J does not have an epoch. J's native representation of date and time is a six element list: year, month, day, hour, minute, second. For example:
<lang j> 6!:0 2011 8 8 20 25 44.725</lang>
(August 8, 2011, 8:25:44 pm)
That said, the 'dates' library does have an epoch:
<lang j> require'dates'
todate 0
1800 1 1</lang>
Java
DateFormat is needed to set the timezone. Printing date alone would show this date in the timezone/locale of the machine that the program is running on. The epoch used in java.util.Date (as well as java.sql.Date, which can be subbed into this example) is actually in GMT, but there isn't a significant difference between that and UTC for lots of applications (documentation for java.util.Date).
<lang java>import java.text.DateFormat;
import java.util.Date;
import java.util.TimeZone;
public class DateTest{
public static void main(String[] args) {
Date date = new Date(0);
DateFormat format = DateFormat.getDateTimeInstance();
format.setTimeZone(TimeZone.getTimeZone("UTC"));
System.out.println(format.format(date));
}
}</lang> Output:
Jan 1, 1970 12:00:00 AM
JavaScript
<lang javascript>document.write(new Date(0).toUTCString());</lang> Output:
Thu, 01 Jan 1970 00:00:00 GMT
Perl
<lang perl>print scalar gmtime 0, "\n";</lang>
Output:
Thu Jan 1 00:00:00 1970
Perl 6
<lang perl6>say DateTime.new(0)</lang>
1970-01-01T00:00:00Z
PHP
<lang php><?php echo gmdate('r', 0), "\n"; ?></lang>
Output:
Thu, 01 Jan 1970 00:00:00 +0000
PicoLisp
The 'date' function in PicoLisp returns a day number, starting first of March of the year zero. Calculated according to the gregorian calendar (despite that that calendar wasn't used in 0 AD yet). <lang PicoLisp>: (date 1) -> (0 3 1) # Year zero, March 1st</lang>
PowerShell
PowerShell uses .NET's DateTime structure and an integer can simply be casted appropriately:
<lang powershell>[datetime] 0</lang>
Output:
Monday, January 01, 0001 12:00:00 AM
Python
<lang python>>>> import time >>> time.asctime(time.gmtime(0)) 'Thu Jan 1 00:00:00 1970' >>></lang>
Ruby
<lang ruby>irb(main):001:0> Time.at(0).utc => 1970-01-01 00:00:00 UTC</lang>
Standard ML
<lang sml>- Date.toString (Date.fromTimeUniv Time.zeroTime); val it = "Thu Jan 1 00:00:00 1970" : string</lang>
Tcl
<lang tcl>% clock format 0 -gmt 1 Thu Jan 01 00:00:00 GMT 1970</lang>
UNIX Shell
The nonstandard option date -r takes seconds from the epoch, and prints date and time. See date(1) manual.
<lang bash>$ date -ur 0 Thu Jan 1 00:00:00 UTC 1970</lang>
Visual Basic
<lang vb>Sub Main()
Debug.Print Format(0, "dd mmm yyyy hh:mm")
End Sub</lang>
Output (in debug window):
30 Dec 1899 00:00