Sleep

Write a program that does the following in this order:

Input an amount of time to sleep in whatever units are most natural for your language (milliseconds, seconds, ticks, etc.). This unit should be noted in comments or in a description.
Print "Sleeping..."
Sleep the main thread for the given amount of time.
Print "Awake!"
End.

AutoHotkey

<lang AutoHotkey>TrayTip, sleeping, sleeping sleep, 2000 ; 2 seconds TrayTip, awake, awake Msgbox, awake</lang>

<lang AutoIt>#AutoIt Version: 3.2.10.0 $sleep_me=InputBox("Sleep", "Number of seconds to sleep", "10", "", -1, -1, 0, 0) Dim $sleep_millisec=$sleep_me*1000 MsgBox(0,"Sleep","Sleeping for "&$sleep_me&" sec") sleep ($sleep_millisec) MsgBox(0,"Awake","... Awaking")</lang>

BASIC

Works with: QuickBasic version 4.5

<lang qbasic>INPUT sec 'the SLEEP command takes seconds PRINT "Sleeping..." SLEEP sec PRINT "Awake!"</lang> "SLEEP" with no argument will sleep until a button is pressed on the keyboard (including modifier keys such as shift or control). Also, pressing a key while SLEEP is waiting for a specific amount of time (as above) will end the SLEEP.

ZX Spectrum Basic

Pressing a key will cut the pause short on the ZX Spectrum.

<lang zxbasic>10 REM s is the number of seconds 20 LET s = 5 30 PRINT "Sleeping" 40 PAUSE s * 50 50 PRINT "Awake"</lang>

Batch File

The usual way to do this is to use the ping utility which waits a second between multiple tries. To wait n seconds one tells ping to make n + 1 tries and redirects the output:

Works with: Windows NT version 4

<lang dos>@echo off set /p Seconds=Enter the number of seconds to sleep: set /a Seconds+=1 echo Sleeping ... ping -n %Seconds% localhost >nul 2>&1 echo Awake!</lang> A similar trick can be used to wait a certain number of milliseconds. The ping utility includes a /w option which specifies the timeout to wait for a reply. This coupled with an unreachable address (where the full timeout will be needed) leads to the following:

Works with: Windows 2000

<lang dos>@echo off set /p MilliSeconds=Enter the number of milliseconds to sleep: echo Sleeping ... ping -n 1 -w %MilliSeconds% 1.2.3.4 >nul 2>&1 echo Awake!</lang>

Starting with Windows Vista there is a command-line utility to wait a number of seconds:

Works with: Windows Vista

<lang dos>@echo off set /p Seconds=Enter the number of seconds to sleep: echo Sleeping ... timeout /t %Seconds% /nobreak >nul echo Awake!</lang>

C

Works with: POSIX

The function sleep needs seconds, which are read from the standard input.

<lang c>#include <stdio.h>

include <unistd.h>

int main() {

 unsigned int seconds;
 scanf("%u", &seconds);
 printf("Sleeping...\n");
 sleep(seconds);
 printf("Awake!\n");
 return 0;

}</lang>

C++

Works with: C++11

<lang cpp>#include <iostream>

include <thread>
include <chrono>

int main() {

   unsigned long microseconds;
   std::cin >> microseconds;
   std::cout << "Sleeping..." << std::endl;
   std::this_thread::sleep_for(std::chrono::microseconds(microseconds));
   std::cout << "Awake!\n";

} </lang>

Works with: POSIX

<lang cpp>#include <unistd.h>

include <iostream>

using namespace std;

int main(int argc, char* argv[]) {

   useconds_t microseconds;
   cin >> microseconds;
   cout << "Sleeping..." << endl;
   usleep(microseconds);
   cout << "Awake!" << endl;
   return 0;

}</lang>

C#

<lang csharp>using System; using System.Threading;

class Program {

   static void Main(string[] args)
   {
       int sleep = Convert.ToInt32(Console.ReadLine());
       Console.WriteLine("Sleeping...");
       Thread.Sleep(sleep); //milliseconds
       Console.WriteLine("Awake!");
   }

}</lang>

Clojure

<lang clojure>(defn sleep [ms] ; time in milliseconds

 (println "Sleeping...")
 (Thread/sleep ms)
 (println "Awake!"))

call it

(sleep 1000)</lang>

Common Lisp

<lang lisp>(defun test-sleep ()

 (let ((seconds (read)))
   (format t "Sleeping...~%")
   (sleep seconds)
   (format t "Awake!~%")))

(test-sleep)</lang>

D

<lang d>import std.c.time; import std.stdio; import std.string; void main() {

 writef("Enter a time(seconds) to sleep: ");
 writefln("Sleeping...");
 sleep(atoi(readln())*1000);
 writefln("Awake!");

}</lang>

Delphi

<lang Delphi>program SleepOneSecond;

{$APPTYPE CONSOLE}

uses SysUtils;

var

 lTimeToSleep: Integer;

begin

 if ParamCount = 0 then
   lTimeToSleep := 1000
 else
   lTimeToSleep := StrToInt(ParamStr(1));
 WriteLn('Sleeping...');
 Sleep(lTimeToSleep); // milliseconds
 WriteLn('Awake!');

end.</lang>

E

You can't do that.

No, really. E's approach to timing, concurrency, and IO is non-blocking; if you want to wait for something, you say what you want to do when it happens — i.e. callbacks. There are no threads of control which can be stopped — except automatically when they just have nothing to do.

So, the closest thing possible to the task description is to wait for the specified time to pass, then do whatever the next thing is.

<lang e>def sleep(milliseconds :int, nextThing) {

   stdout.println("Sleeping...")
   timer.whenPast(timer.now() + milliseconds, fn {
       stdout.println("Awake!")
       nextThing()
   })

}</lang>

Eiffel

The feature sleep is defined in the library class EXECUTION_ENVIRONMENT. So the demonstration class APPLICATION inherits from EXECUTION_ENVIRONMENT in order to make sleep available.

sleep takes an argument which declares the number of nanoseconds to suspend the thread's execution.

<lang eiffel >class

   APPLICATION

inherit

   EXECUTION_ENVIRONMENT

create

   make

feature -- Initialization

   make
           -- Sleep for a given number of nanoseconds.
       do
           print ("Enter a number of nanoseconds: ")
           io.read_integer_64
           print ("Sleeping...%N")
           sleep (io.last_integer_64)
           print ("Awake!%N")
       end

end</lang>

Output (sleeping 10 seconds):

Enter a number of nanoseconds: 10000000000
Sleeping...
Awake!

Erlang

Erlang doesn't really have such a thing as a main thread. However, sleeping any process can be done with the timer:sleep/1 function: <lang erlang>main() ->

   io:format("Sleeping...~n"),
   timer:sleep(1000), %% in milliseconds
   io:format("Awake!~n").</lang>

It is to be noted that Erlang's sleep function is implemented in Erlang with a timeout on a receive, so you may sometimes encounter the following way of sleeping a process: <lang erlang>main() ->

   io:format("Sleeping...~n"),
   receive
   after 1000 -> ok %% in milliseconds
   end,
   io:format("Awake!~n").</lang>

which is the way it is implemented in the timer module.

Factor

<lang factor>USING: calendar io math.parser threads ;

read-sleep ( -- )

   readln string>number seconds
   "Sleeping..." print
   sleep
   "Awake!" print ;</lang>

Fantom

Fantom has a 'Duration' class, which uses time definitions with units: e.g., 5sec, 100ns, 5hr. These are used for input in the following program.

<lang fantom> using concurrent

class Main {

 public static Void main ()
 {
   echo ("Enter a time to sleep: ")
   input := Env.cur.in.readLine
   try
   {
     time := Duration.fromStr (input)
     echo ("sleeping ...")
     Actor.sleep (time)
     echo ("awake!")
   }
   catch
   {
     echo ("Invalid time entered")
   }
 }

} </lang>

Output:

Enter a time to sleep: 
5sec
sleeping ...
awake!

Forth

<lang forth>: sleep ( ms -- )

 ." Sleeping..."
 ms
 ." awake." cr ;</lang>

Fortran

<lang fortran>program test_sleep

 implicit none
 integer :: iostat
 integer :: seconds
 character (32) :: argument

 if (iargc () == 1) then
   call getarg (1, argument)
   read (argument, *, iostat = iostat) seconds
   if (iostat == 0) then
     write (*, '(a)') 'Sleeping...'
     call sleep (seconds)
     write (*, '(a)') 'Awake!'
   end if
 end if

end program test_sleep</lang>

Frink

In Frink, all values have units of measure, and sleep functions take units of time, which can be seconds, nanoseconds, minutes, hours, etc. The user may enter values like "3 hours" or "1 ms". The units of measure are captured as first-class values in the language, and not hidden in comments nor implied in APIs. <lang frink> do

 t = eval[input["Enter amount of time to sleep: ", "1 second"]]

while ! (t conforms time)

println["Sleeping..."] sleep[t] println["Awake!"] </lang>

Go

Technically, this varies from the task by sleeping the main goroutine rather than the main thread. The Go runtime multiplexes goroutines to operating system threads and the language does not provide direct access to threads. <lang go>package main

import "time" import "fmt"

func main() {

   fmt.Print("Enter number of seconds to sleep: ")
   var sec float64
   fmt.Scanf("%f", &sec)
   fmt.Print("Sleeping…")
   time.Sleep(time.Duration(sec * float64(time.Second)))
   fmt.Println("\nAwake!")

}</lang>

Groovy

Solution: <lang groovy>def sleepTest = {

   println("Sleeping...")
   sleep(it)
   println("Awake!")

}</lang>

Test: <lang groovy>sleepTest(1000) print Hmmm. That was... less than satisfying. How about this instead? Thread.start {

   (0..5).each {
       println it
       sleep(1000)
   }

} sleepTest(5000)</lang>

Output:

Sleeping...
Awake!

Hmmm. That was... less than satisfying
How about this instead?
Sleeping...
0
1
2
3
4
Awake!
5

Haskell

<lang haskell>import Control.Concurrent

main = do seconds <- readLn

         putStrLn "Sleeping..."
         threadDelay $ round $ seconds * 1000000
         putStrLn "Awake!"</lang>

HicEst

<lang hicest>DLG(NameEdit = milliseconds, Button = "Go to sleep") WRITE(StatusBar) "Sleeping ... " SYSTEM(WAIT = milliseconds) WRITE(Messagebox) "Awake!"</lang>

IDL

<lang IDL> read,i,prompt='Input sleep time in seconds: ' print,'Sleeping...' wait,i ; in seconds, but accepts floats(/fractional) as input print,'Awake!' </lang>

Icon and Unicon

<lang Icon>procedure main()

repeat {

  writes("Enter number of seconds to sleep :")
  s := reads()
  if s = ( 0 < integer(s)) then break
  }

write("\nSleeping for ",s," seconds.") delay(1000 * s) write("Awake!") end</lang>

J

Solution: <lang j>sleep =: 6!:3

sleeping=: monad define

 smoutput 'Sleeping...'
 sleep y
 smoutput 'Awake!'

)</lang>

Example: <lang j> sleeping 0.500 NB. Sleep 500 milliseconds Sleeping... Awake!</lang>

Java

Works with: Java version 1.5+

<lang java5> import java.util.InputMismatchException; import java.util.Scanner;

public class Sleep {

   public static void main(final String[] args) throws InterruptedException {
       try {
           int ms = new Scanner(System.in).nextInt(); //Java's sleep method accepts milliseconds
           System.out.println("Sleeping...");
           Thread.sleep(ms);
           System.out.println("Awake!");
       } catch (InputMismatchException inputMismatchException) {
           System.err.println("Exception: " + inputMismatchException);
       }
   }

}</lang>

JavaScript (in a web browser)

Generally, JavaScript in a web browser is event-loop based and (except for alert()) non-blocking. So, the closest thing possible to the task description is to do something once the specified time has passed.

 setTimeout(function () {
   document.write('Awake!')
 }, prompt("Number of milliseconds to sleep"));

 document.write('Sleeping... ');

</script></lang>

LabVIEW

Uses milliseconds. LabVIEW has no "main thread" so it must be forced with a sequence structure.
This image is a VI Snippet, an executable image of LabVIEW code. The LabVIEW version is shown on the top-right hand corner. You can download it, then drag-and-drop it onto the LabVIEW block diagram from a file browser, and it will appear as runnable, editable code.

Liberty BASIC

<lang lb>Input "Please input the number of milliseconds you would like to sleep. "; sleeptime Print "Sleeping..." CallDLL #kernel32, "Sleep", sleeptime As long, ret As void Print "Awake!"

</lang>

Logo

<lang logo> to sleep :n print [Sleeping...] wait :n ; units: 1/60th of a second print [Awake.] end </lang>

Mathematica

This function, as you can probably guess, takes its argument in seconds. While this function does tie up execution (but not with a busy wait), the Mathematica front end remains fully functional and can be used to stop the sleeping with Evaluation -> Abort Evaluation.

<lang Mathematica> Sleep[seconds_] := (Print["Sleeping..."]; Pause[seconds]; Print["Awake!"];) </lang>

MATLAB / Octave

<lang MATLAB>function sleep()

   time = input('How many seconds would you like me to sleep for? ');
   assert(time > .01);
   disp('Sleeping...');
   pause(time);
   disp('Awake!');

end</lang>

NewLISP

<lang NewLISP>(println "Sleeping..." ) (sleep 2000) ; Wait for 2 seconds (println "Awake!")</lang>

Objective-C

Of course the same code of Sleep#C works for Objective-C. The following code uses a OpenStep derived framework (Cocoa, GNUstep...).

Works with: GNUstep

and

Works with: Cocoa

<lang objc>#import <Foundation/Foundation.h>

int main() {

 NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
 NSTimeInterval sleeptime;

 printf("wait time in seconds: ");
 scanf("%f", &sleeptime);

 NSLog(@"sleeping...");
 [NSThread sleepForTimeInterval: sleeptime];
 NSLog(@"awakening...");

 [pool release];
 return 0;

}</lang>

Objeck

<lang objeck> bundle Default {

 class Test {
   function : Main(args : System.String[]) ~ Nil {
     if(args->Size() = 1) {
       "Sleeping..."->PrintLine();
       Thread->Sleep(args[0]->ToInt());
       "Awake!"->PrintLine();
     };
   }
 }

} </lang>

OCaml

<lang ocaml>#load "unix.cma";; let seconds = read_int ();; print_endline "Sleeping...";; Unix.sleep seconds;; (* number is integer in seconds *) print_endline "Awake!";;</lang>

or <lang ocaml>#load "unix.cma";;

directory "+threads";;
load "threads.cma";;

let seconds = read_float ();; print_endline "Sleeping...";; Thread.delay seconds;; (* number is in seconds ... but accepts fractions *) print_endline "Awake!";;</lang>

Oz

<lang oz>declare

 class TextFile from Open.file Open.text end
 StdIn = {New TextFile init(name:stdin)}
 WaitTime = {String.toInt {StdIn getS($)}}

in

 {System.showInfo "Sleeping..."}
 {Delay WaitTime} %% in milliseconds
 {System.showInfo "Awake!"}</lang>

PARI/GP

GP does not have threading built in and so cannot truly sleep; this is code for spin-idling.

gettime

The units are milliseconds. <lang parigp>sleep(ms)={

 print("Sleeping...");
 while((ms-=gettime()) > 0,);
 print("Awake!")

};

sleep(input())</lang>

alarm

Works with: PARI/GP version 2.4.3 and above on Linux

The units are seconds. <lang parigp>sleep(s)={

 print("Sleeping...");
 alarm(s);
 trap(alarmer,,while(1,));
 print("Awake!")

};

sleep(input())</lang>

Pascal

See Delphi

Perl

seconds: <lang perl>$seconds = <>; print "Sleeping...\n"; sleep $seconds; # number is in seconds print "Awake!\n";</lang>

microseconds and nanoseconds using the Time::HiRes module: <lang perl>use Time::HiRes qw( usleep nanosleep );

$microseconds = <>; print "Sleeping...\n"; usleep $microseconds; print "Awake!\n";

$nanoseconds = <>; print "Sleeping...\n"; nanosleep $nanoseconds; print "Awake!\n";</lang>

Perl 6

The sleep function argument is in units of seconds, but these may be fractional (to the limits of your system's clock).

<lang perl6>my $sec = prompt("Sleep for how many microfortnights? ") * 1.2096; say "Sleeping..."; sleep $sec; say "Awake!";</lang>

Note that 1.2096 is a rational number in Perl 6, not floating point, so precision can be maintained even when dealing with very small powers of ten.

PHP

seconds: <lang php>$seconds = 42; echo "Sleeping...\n"; sleep($seconds); # number is integer in seconds echo "Awake!\n";</lang>

microseconds: <lang php>$microseconds = 42000000; echo "Sleeping...\n"; usleep($microseconds); # number is integer in microseconds echo "Awake!\n";</lang>

nanoseconds: <lang php>$nanoseconds = 42000000000; echo "Sleeping...\n"; time_nanosleep($seconds, $nanoseconds); # first arg in seconds plus second arg in nanoseconds echo "Awake!\n";</lang>

PicoLisp

<lang PicoLisp>(prinl "Sleeping..." ) (wait 2000) # Wait for 2 seconds (prinl "Awake!")</lang> As wait will continue executing background events, another possibility (for a complete stop) is calling some external program like <lang PicoLisp>(prinl "Sleeping..." ) (call 'sleep 2) # Wait for 2 seconds (prinl "Awake!")</lang>

PL/I

<lang PL/I> put ('sleeping'); delay (2000); /* wait for 2 seconds (=2000 milliseconds). */ put ('awake'); </lang>

PowerShell

<lang powershell>$d = [int] (Read-Host Duration in seconds) Write-Host Sleeping ... Start-Sleep $d Write-Host Awake!</lang> The -Milliseconds parameter to Start-Sleep can be used to allow for sub-second precision in sleeping.

Prolog

Works with SWI-Prolog. <lang Prolog>rosetta_sleep(Time) :- writeln('Sleeping...'), sleep(Time), writeln('Awake!'). </lang>

Protium

Literate mode <lang html><@ SAYLIT>Number of seconds: </@><@ GETVAR>secs</@> <@ SAYLIT>Sleeping</@> <@ ACTPAUVAR>secs</@> <@ SAYLIT>Awake</@></lang>

French variable-length opcodes <lang html><# MontrezLittéralement>Number of seconds: </#><# PrenezUneValeurVariable>secs</#> <# MontrezLittéralement>Sleeping</#> <# AgissezFaireUnePauseVariable>secs</#> <# MontrezLittéralement>Awake</#></lang>

(Simplified) Chinese fixed-length opcodes <lang html><@ 显示_字串_>Number of seconds: </@><@ 获取_变量_>secs</@> <@ 显示_字串_>Sleeping</@> <@ 运行_暂停动变量_>secs</@> <@ 显示_字串_>Awake</@></lang>

PureBasic

Sleeping is performed with Delay() and a value in milliseconds. The time is accurate to approximately +/- 15 milliseconds. <lang PureBasic>If OpenConsole()

 Print("Enter a time(milliseconds) to sleep: ")
 x.i = Val(Input())
 PrintN("Sleeping...")
 Delay(x) ;in milliseconds
 PrintN("Awake!")
 Print(#CRLF$ + #CRLF$ + "Press ENTER to exit")
 Input()
 CloseConsole()

EndIf</lang>

Python

<lang python>import time

seconds = float(raw_input()) print "Sleeping..." time.sleep(seconds) # number is in seconds ... but accepts fractions print "Awake!"</lang>

R

The call to flush.console is only needed if buffering is turned on. See FAQ for R on windows. The time is given in seconds (fractions allowed, resolution is system dependent). <lang R> sleep <- function(time=1) {

  message("Sleeping...")
  flush.console()      
  Sys.sleep(time)
  message("Awake!")

}

sleep() </lang>

REBOL

<lang REBOL>REBOL [

   Title: "Sleep Main Thread"
   Date: 2009-12-15
   Author: oofoe
   URL: http://rosettacode.org/wiki/Sleep_the_Main_Thread

]

naptime: to-integer ask "Please enter sleep time in seconds: " print "Sleeping..." wait naptime print "Awake!"</lang>

Retro

Retro has no fine grained timer; so we have to make due with seconds.

<lang Retro>: sleep ( n- )

 [ time [ time over - 1 > ] until drop ] times ;
 : test
   "\nTime to sleep (in seconds): " puts getToken toNumber
   "\nSleeping..." sleep
   "\nAwake!\n" ;</lang>

REXX

Not all REXX interpretors have the DELAY built-in function. <lang rexx> /*REXX program to sleep x seconds (base in the argument). */

parse arg secs . /*get a (possible) argument. */ secs=word(secs 0,1) /*if not present, assume 0 (zero)*/ say 'Sleeping' secs "seconds." /*tell 'em what's happening. */ call delay(secs) /*snooze. Hopefully, a short nap*/ say 'Awake!' /*and tell 'em we're running. */ </lang> Output after the following was used for input:

4.7

Sleeping 4.7 seconds.
Awake!

Ruby

<lang ruby>seconds = gets.to_f puts "Sleeping..." sleep(seconds) # number is in seconds ... but accepts fractions

Minimum resolution is system dependent.

puts "Awake!"</lang>

Scala

<lang scala>import java.util.Scanner

object Sleeper extends Application { val input = new Scanner(System.in) val ms = input.nextInt System.out.println("Sleeping...") Thread.sleep(ms) System.out.println("Awake!") }</lang>

Scheme

Many Scheme implementations support srfi-18, a multithreading library which provides a 'thread-sleep!' function. The following works in Chicken Scheme:

<lang scheme> (use format) (use srfi-18)

(format #t "Enter a time (in seconds): ") (let ((time (read))) ; converts input to a number, if possible

 (if (number? time)
   (begin
     (format #t "Sleeping...~&")
     (thread-sleep! time)
     (format #t "Awake!~&"))
   (format #t "You must enter a number~&")))

</lang>

Scheme implementations also provide alternative approaches. For example, Chicken Scheme has a 'posix' library which includes a 'sleep' function.

Seed7

The duration.s7i library defines the function wait, which takes an argument of type duration. Functions to create durations with years, months, days, hours, minutes, seconds and micro seconds exist also.

<lang seed7>$ include "seed7_05.s7i";

 include "duration.s7i";

const proc: main is func

 local
   var integer: secondsToSleep is 0;
 begin
   write("Enter number of seconds to sleep: ");
   readln(secondsToSleep);
   writeln("Sleeping...");
   wait(secondsToSleep . SECONDS);
   writeln("Awake!");
 end func;</lang>

Smalltalk

(Pharo) <lang smalltalk> t := (FillInTheBlankMorph request: 'Enter time in seconds') asNumber. Transcript show: 'Sleeping...'. (Delay forSeconds: t) wait. Transcript show: 'Awake!'. </lang>

Standard ML

<lang ocaml>(TextIO.print "input a number of seconds please: "; let val seconds = valOf (Int.fromString (valOf (TextIO.inputLine TextIO.stdIn))) in

 TextIO.print "Sleeping...\n";
 OS.Process.sleep (Time.fromReal seconds);  (* it takes a Time.time data structure as arg,
                                              but in my implementation it seems to round down to the nearest second.
                                              I dunno why; it doesn't say anything about this in the documentation *)
 TextIO.print "Awake!\n"

end)</lang>

Suneido

<lang Suneido>function (time)

   {
   Print("Sleeping...")
   Sleep(time) // time is in milliseconds
   Print("Awake!")
   }</lang>

Tcl

Blocking example (the process is blocked preventing any background activity). <lang tcl>puts -nonewline "Enter a number of milliseconds to sleep: " flush stdout set millis [gets stdin] puts Sleeping... after $millis puts Awake!</lang>

A non-blocking example where background activity will occur. <lang tcl>puts -nonewline "Enter a number of milliseconds to sleep: " flush stdout set millis [gets stdin] set ::wakupflag 0 puts Sleeping... after $millis set ::wakeupflag 1 vwait ::wakeupflag puts Awake!</lang>

TI-89 BASIC

This example is in need of improvement:

Do something less wasteful than a busy wait, if possible.

Local dur_secs,st0,st,seconds
Define seconds() = Func
  Local hms
  getTime()→hms
  Return ((hms[1] * 60 + hms[2]) * 60) + hms[3]
EndFunc
ClockOn
  
Prompt dur_secs
Disp "Sleeping..."
seconds()→st
st→st0
While when(st<st0, st+86400, st) - st0 < dur_secs
  seconds()→st
EndWhile
Disp "Awake!"

Toka

This makes use of the sleep() function from libc which suspends execution for a specified number of seconds.

1 import sleep as sleep()
[ ." Sleeping...\n" sleep() drop ." Awake!\n" bye ] is sleep

45 sleep