System time

From Rosetta Code

Output the system time (any units will do as long as they are noted) either by a system command or one built into the language. The system time can be used for debugging, network information, random number seeds, or something as simple as program performance.

Contents 1 Ada 2 BASIC 3 C 4 Common Lisp 5 Forth 6 Fortran 7 Haskell 8 Io 9 J 10 Java 11 OCaml 12 Perl 13 Python 14 Ruby 15 See Also

[edit] Ada

The following example displays a date-time stamp. The time zone value is the number of minutes offset from the prime meridian.

with Ada.Calendar; use Ada.Calendar;
with Ada.Calendar.Formatting; use Ada.Calendar.Formatting;
with Ada.Calendar.Time_Zones; use Ada.Calendar.Time_Zones;
with Ada.Text_Io; use Ada.Text_Io;

procedure System_Time is
   Now : Time := Clock;
begin
   Put_line(Image(Date => Now, Time_Zone => -7*60));
end System_Time;

Output:

2008-01-23 19:14:19

[edit] BASIC

Works with: QuickBasic version 4.5

This shows the system time in seconds since midnight.

PRINT TIMER

[edit] C

This probably isn't the best way to do this, but it works. It shows system time as "Www Mmm dd hh:mm:ss yyyy", where Www is the weekday, Mmm the month in letters, dd the day of the month, hh:mm:ss the time, and yyyy the year.

#include<time.h>
#include<stdio.h>
#include<stdlib.h>
int main(){
  time_t my_time = time(NULL);
  printf("%s", ctime(&my_time));
  return 0;
}

[edit] Common Lisp

(multiple-value-bind (second minute hour day month year) (get-decoded-time)
	   (format t "~4,'0D-~2,'0D-~2,'0D ~2,'0D:~2,'0D:~2,'0D" year month day hour minute second))

[edit] Forth

Forth's only standard access to the system timers is via DATE&TIME ( -- s m h D M Y ) and MS ( n -- ) which pauses the program for at least n milliseconds. Particular Forth implementations give different access to millisecond and microsecond timers:

Works with: Win32Forth

Works with: GNU Forth

Works with: bigFORTH

Works with: iForth

Works with: PFE

Works with: SwiftForth

Works with: VFX Forth

Works with: MacForth

[UNDEFINED] MS@ [IF]                                   \ Win32Forth (rolls over daily)
 [DEFINED] ?MS [IF] ( -- ms )
   : ms@ ?MS ;                                         \ iForth
 [ELSE] [DEFINED] cputime [IF] ( -- Dusec )
   : ms@ cputime d+ 1000 um/mod nip ;                  \ gforth: Anton Ertl
 [ELSE] [DEFINED] timer@ [IF] ( -- Dusec )
   : ms@ timer@ >us 1000 um/mod nip ;                  \ bigForth
 [ELSE] [DEFINED] gettimeofday [IF] ( -- usec sec )
   : ms@ gettimeofday 1000 MOD 1000 * SWAP 1000 / + ;  \ PFE
 [ELSE] [DEFINED] counter [IF]
   : ms@ counter ;                                     \ SwiftForth
 [ELSE] [DEFINED] GetTickCount [IF]
   : ms@ GetTickCount ;                                \ VFX Forth
 [ELSE] [DEFINED] MICROSECS [IF]
   : ms@  microsecs 1000 UM/MOD nip ;                  \  MacForth
[THEN] [THEN] [THEN] [THEN] [THEN] [THEN] [THEN]

MS@ .   \ print millisecond counter

[edit] Fortran

In ISO Fortran 90 or later, use the SYSTEM_CLOCK intrinsic subroutine:

     integer :: start, stop, rate
     real :: result
     
     ! optional 1st integer argument (COUNT) is current raw system clock counter value (not UNIX epoch millis!!)
     ! optional 2nd integer argument (COUNT_RATE) is clock cycles per second
     ! optional 3rd integer argument (COUNT_MAX) is maximum clock counter value
     call system_clock( start, rate )
     
     result = do_timed_work()
     
     call system_clock( stop )
     
     print *, "elapsed time: ", real(stop - start) / real(rate)

In ISO Fortran 95 or later, use the CPU_TIME intrinsic subroutine:

     real :: start, stop
     real :: result
     
     ! System clock value interpreted as floating point seconds
     call cpu_time( start )
     
     result = do_timed_work()
     
     call cpu_time( stop )
     
     print *, "elapsed time: ", stop - start

[edit] Haskell

import System.Time

do
  ct <- getClockTime
  cal <- toCalendarTime ct
  putStrLn $ calendarTimeToString cal -- default format
  putStrLn $ formatCalendarTime System.Locale.defaultTimeLocale "%a %b %e %H:%M:%S %Y" cal

[edit] Io

Date now println

Example output:

2008-08-26 00:15:52 EDT

[edit] J

The external verb 6!:0 returns a six-element floating-point array in which the elements correspond to year, month, day, hour, minute, and second. Fractional portion of second is given to thousandths.

   6!:0 ''
2008 1 23 12 52 10.341

[edit] Java

This shows the system time in POSIX time.

import java.util.Date;
 
 public class SystemTime{
    public static void main(String[] args){
       Date now = new Date();
       System.out.println(now.getTime());
       //System.currentTimeMillis() returns the same value
    }
 }

Other methods are available in the Date object such as: getDay(), getHours(), getMinutes(), getSeconds(), getYear(), etc.

[edit] OCaml

#load "unix.cma";;
open Unix;;
let {tm_sec = sec;
     tm_min = min;
     tm_hour = hour;
     tm_mday = mday;
     tm_mon = mon;
     tm_year = year;
     tm_wday = wday;
     tm_yday = yday;
     tm_isdst = isdst} = localtime (time ());;
Printf.printf "%04d-%02d-%02d %02d:%02d:%02d\n" (year + 1900) (mon + 1) mday hour min sec;;

[edit] Perl

Simple localtime use in scalar context.

print scalar localtime, "\n";

Output:

Thu Jan 24 11:23:30 2008

localtime use in array context.

($sec, $min, $hour, $mday, $mon, $year, $wday, $yday, $isdst) = localtime;
printf("%04d-%02d-%02d %02d:%02d:%02d\n", $year + 1900, $mon + 1, $mday, $hour, $min, $sec);

Output:

2008-01-24 11:23:30

localtime use in array context with POSIX strftime.

use POSIX qw(strftime);

$now_string = strftime "%a %b %e %H:%M:%S %Y", localtime;
print "$now_string\n";

Output (with cs_CZ.UTF-8 locale):

Čt led 24 11:23:30 2008

[edit] Python

import time
print time.ctime()

[edit] Ruby

puts Time.now

[edit] See Also

Date format

Retrieving system time (wiki)