Shortest code to produce non-deterministic output

Question

You need to produce output that is non-deterministic.

In this case, this will be defined to mean that the output will not always be the same result.

Rules:

• A pseudo-random number generator that always has the same seed does not count.

• You can rely on the program being run at a different (unknown) time each execution.

• Your code's process id (if it's not fixed by the interpreter) can be assumed to be non-deterministic.

• You may rely on web-based randomness.

• Your code may not take non-empty input. Related meta post.

• The program is not required to halt, but the output must be displayed.

Leaderboard

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Answer 1

huh?, 0 bytes

An empty program still produces output. The last lines of the Python interpreter that are executed:

print "..."
f = open('Notes.txt', 'w')
f.write(time.strftime("%c") + " - The user tried to give me commands again. I still have no idea what they are talking about...\n")

At the end of a program, the Python interpreter will print ..., then it will create/open a text file called Notes.txt and write a string which contains the current time in front.

Answer 2

WinDbg, 1 byte

#

Wow! Never expected a 1 byte solution from WinDbg!

# searches for a disassembly pattern, but since there's no parameters, it looks to just return the next assembly instruction in whatever dump/process you're attached to. Not sure the logic for setting the initial address, but it does.

Sample output:

0:000> #
Search address set to 75959556 
user32!NtUserGetMessage+0xc
75959556 c21000          ret     10h

0:000> #
user32!NtUserGetMessage+0xf 
75959559 90              nop

0:000> #
user32!NtUserMessageCall 
7595955a 90              nop

0:000> #
user32!NtUserMessageCall+0x1 
7595955b 90              nop

0:000> #
user32!NtUserMessageCall+0x2 
7595955c 90              nop

0:000> #
user32!NtUserMessageCall+0x3 
7595955d 90              nop

0:000> #
user32!GetMessageW
7595955e 8bff            mov     edi,edi

0:000> #
user32!GetMessageW+0x2 
75959560 55              push    ebp

0:000> #
user32!GetMessageW+0x3 
75959561 8bec            mov     ebp,esp

0:000> #
user32!GetMessageW+0x5 
75959563 8b5510          mov     edx,dword ptr [ebp+10h]

Answer 3

Java 7, 33 30 27 bytes

int a(){return hashCode();}

Because Java.

Answer 4

MATLAB, 3 bytes

why

why provides answers to almost any question. A few examples:

why
The programmer suggested it.

why
To fool the tall good and smart system manager. 

why
You insisted on it.

why
How should I know?

This is shorter than any rand function I can think of.

Answer 5

R, 1 byte

t

Outputs the function's source code and a memory pointer address which changes with every (re-)start of R.

Answer 6

Befunge (-93 and -98), 3 bytes

?.@

The ? sends execution in a random direction. If it goes up or down, it loops back to the ? and rerolls. If it goes left, the program wraps round to the @ and thus exits without printing anything. If it goes right, it prints 0 (the output produced by . when the stack is empty) and then exits on the @.

Answer 7

Labyrinth, 5 bytes

v
!
@

Either prints 0 or nothing (50% chance each).

Try it online!

There is a very specific case in which Labyrinth exhibits random behaviour:

• There must be a wall in front of the instruction pointer and behind it.
• There must be a non-wall left and right of the instruction pointer.
• The current top of the stack must be zero.

If all of those conditions are met, the direction the IP moves in is chosen (uniformly) randomly. The cherry on top is that those three conditions are impossible to meet in regular control flow, which means unless you modify the source code at runtime.

(This may seem a bit arbitrary, but it's actually the most consistent behaviour I could find for these conditions, since normally the direction of the IP always depends on the previous direction, its neighbours, and the sign of the top of the stack, and this seemed like an elegant way to include a source of randomness in the language.)

With the help of the source code rotation instructions (<^>v) it's possible to bring the IP into this situation. One such example is seen at the top. The IP initially points east and starts at the top. The v rotates the current column so that we get:

@
v
!

The IP moves along with this rotation so that it's still on the v, pointing east. All the conditions are fulfilled now, so the IP will either go up or down randomly. If it goes up, the program terminates immediately. If it goes down, it prints a zero, rotates the column again, and then terminates.

There are three other programs making use of this (one which also prints 0, one which prints 00 and one which prints 000):

v
@
!

"
>@!

"
>!@

(Actually there are a lot more than three other programs, because you could also use . instead of ! to print null bytes, or replace that " with a large variety of commands, but I believe they all work essentially the same.)

Answer 8

Minecraft, 5 4 bytes

op 8

Used by typing into a server's console or a command block and giving it power. Can be run from the chat interface by prepending a /.

Usually this does nothing, but if there's a player with the username "8" on the server, they will be given operator permissions. Note that while Minecraft normally requires usernames to be 3 characters long, some accounts with shorter name lengths were created before this restriction.

The version that can be demonstrated to be non-deterministic without one of these usernames or risk of giving a user operator permissions is here:

me @r

Displays a message to everyone, the message being the username of a random player. The op command only takes a string literal, not any script that returns a string.

The me command wouldn't really work for the first example, it would display "<your-username> 8". When run from a command block, it wouldn't be deterministic since all command blocks have the same "username" but running it from the chat interface would require the / for one extra byte.

Answer 9

sh + procps, 1 byte

w

This is the shortest solution I'm aware of that works via calling into external executables. procps is the responsible package for reporting information about the current system state (ps and friends), and is installed on most Linux distributions by default; w is the shortest-named command in it, and returns information about the logged-in users, but also some nondeterministic information like uptime.

Answer 10

JavaScript, 4 bytes

Date

A function which returns the current date/time. I think this is the shortest it will get...

Explanation

Since this seems to be causing a lot of confusion as to why it's valid, I'll try to explain.

In JavaScript, a function entry is valid if it can be assigned to a variable and called like a function. For example, this function is a valid entry:

function(){return Date()}

Because it is a function that can be assigned to a variable like so:

f=function(){return Date()}

And then run with f() as many times as necessary. Each time, it returns the current date/time string, which has been ruled non-deterministic by the OP.

This ES6 arrow function is also valid:

_=>Date()

It can be assigned with f=_=>Date(), then run with f() like the other one.

Now, here's another valid entry:

Date

Why? Because just like the other two entries, it can be assigned with f=Date and then called with f(), returning exactly the same thing as the other two. Try it:

var f = Date

<button onclick="console.log(f())">Run</button>

Answer 11

Inform 7, 6 bytes

x is y

This isn't a valid Inform 7 program, since neither "x" nor "y" has been defined. So this throws an error.

However, some of Inform 7's error messages—including this one—are randomized. So the text it prints is technically non-deterministic.

A few possible outputs include:

Problem. The sentence 'x is y' appears to say two things are the same - I am reading 'x' and 'y' as two different things, and therefore it makes no sense to say that one is the other: it would be like saying that 'Adams is Jefferson'. It would be all right if the second thing were the name of a kind, perhaps with properties: for instance 'Virginia is a lighted room' says that something called Virginia exists and that it is a 'room', which is a kind I know about, combined with a property called 'lighted' which I also know about.

Problem. The sentence 'x is y' appears to say two things are the same - I am reading 'x' and 'y' as two different things, and therefore it makes no sense to say that one is the other: it would be like saying that 'Adam is Eve'. It would be all right if the second thing were the name of a kind, perhaps with properties: for instance 'Land of Nod is a lighted room' says that something called Land of Nod exists and that it is a 'room', which is a kind I know about, combined with a property called 'lighted' which I also know about.

Problem. The sentence 'x is y' appears to say two things are the same - I am reading 'x' and 'y' as two different things, and therefore it makes no sense to say that one is the other: it would be like saying that 'Clark Kent is Lex Luthor'. It would be all right if the second thing were the name of a kind, perhaps with properties: for instance 'Metropolis is a lighted room' says that something called Metropolis exists and that it is a 'room', which is a kind I know about, combined with a property called 'lighted' which I also know about.

Problem. The sentence 'x is y' appears to say two things are the same - I am reading 'x' and 'y' as two different things, and therefore it makes no sense to say that one is the other: it would be like saying that 'Aeschylus is Euripides'. It would be all right if the second thing were the name of a kind, perhaps with properties: for instance 'Underworld is a lighted room' says that something called Underworld exists and that it is a 'room', which is a kind I know about, combined with a property called 'lighted' which I also know about.

Answer 12

Bash (procps-ng), 2 bytes

ps

$$ is also a solution.

Answer 13

Python 2, 11 bytes

print id(1)

Answer 14

Pyth, 2 bytes

O0

Explanation:

 0 0
O  Random float in [0, 1)

It's that, when O has 0 as its argument, it simply returns a random float between 0 and 1, exclusive.

Let's do it just for the heck of it!

Also, it seems that this can be sorta retro (thanks to 34718/mbomb007):

---

Pyth, 2 bytes

OT

Explanation:

 T 10
O  Random integer in [0, 10]

Try this boooooooooooooooring version instead >:(

Answer 15

PowerShell, 4 2 bytes

(crossed out 4 still looks like 4)

ps

This is the alias for Get-Process which will output the current process listing as a table, including handles, private memory, CPU time, etc.

Execute it via something like the following:

C:\Tools\Scripts\golfing>powershell.exe "ps"

Answer 16

Zsh, 5 bytes

<<<$$

Prints PID.

Answer 17

Commodore 64 Basic, 4 bytes

1S|0

PETSCII substitution: | = SHIFT+Y

The zero page of a Commodore 64 is an area of 256 bytes of memory that can be accessed faster than the rest of RAM. Consequently, programs (such as the BASIC interpreter) use it for frequently-accessed data, and the CPU itself stores some of its internal state here. The contents are subject to change without notice.

The BASIC program above, ungolfed, is 1 SYS 0, ie. transfer execution to memory location 0. This starts executing the zero page as code. Normally, when the BASIC interpreter starts running a program, the first 16 bytes are

2F 37 00 AA  B1 91 B3 22
22 00 00 4C  00 00 00 00

so SYS 0 would execute the following

00: ROL-AND $37,A  - Undocumented opcode: rotate the value at memory location 0x37 left, and store the result in the accumulator
02: BRK            - Call the interrupt vector

The overall result is to output the BASIC READY. prompt and return control to the user. However, memory location 0x00 is the CPU's I/O direction register, and memory location 0x01 is CPU's I/O address register. If you've done something that changes these before running the program, the results can be unpredictable, ranging from outputting garbage to locking up the computer (the 0x22 usually contained in memory location 0x07, if executed as an instruction, is an undocumented HALT opcode).

Alternatively, a more reliably unpredictable program is the four-byte

1?TI

Prints the elapsed time, in jiffies (1/60 of a second), since system power-on.

Answer 18

05AB1E, 2 bytes

žd

Try it online!

Outputs current microseconds from the executing machine's internal clock.

Or you could do something like this...

05AB1E, 3 bytes

A.r

Try it online!

Outputs a randomly shuffled lower-case alphabet.

Or this also works:

A.R

Try it online!

Outputs a random letter from the alphabet.

Or this also works, and is cooler:

05AB1E, 9 bytes

"ž"A.RJ.V

Try it online!

Outputs randomly one of these:

ž 23  > ža           push current hours
        žb           push current minutes
        žc           push current seconds
        žd           push current microseconds
        že           push current day
        žf           push current month
        žg           push current year
        žh           push [0-9]
        ži           push [a-zA-Z]
        žj           push [a-zA-Z0-9_]
        žk           push [z-aZ-A]
        žl           push [z-aZ-A9-0_]
        žm           push [9-0]
        žn           push [A-Za-z]
        žo           push [Z-Az-a]
        žp           push [Z-A]
        žq           push pi
        žr           push e
        žs           pop a, push pi to a digits (max. 100000)
        žt           pop a, push e to a digits (max. 10000)
        žu           push ()<>[]{}
        žv           push 16
        žw           push 32
        žx           push 64
        žy           push 128
        žz           push 256

Answer 19

C, 25 21 bytes

Thanks to pseudonym117 for saving 4 bytes.

main(i){putchar(&i);}

Compiled with gcc -o test lol.c (yeah I'm quite original with my file's name...), and ran with ./test.

It does what it says: prints the character corresponding to the memory address of i, which is defined at runtime, so it should be non-deterministic.

Answer 20

BrainfuckX and small s.c.r.i.p.t. (etc) polyglot - 2 bytes

?.

? - Randomize the value in the current cell

. - Send current cell to stdout

Answer 21

Python 2, 29 bytes

import os
print os.urandom(9)

Sadly not the first time writing code on a smartphone.

Answer 22

Perl, 5 bytes

say$$

Outputs the process ID and a newline.

Answer 23

Ruby, 3 bytes

p$$

Try it online!

Prints the process ID.

Answer 24

Pyke, 1 byte

C

Try it here!

Outputs the current time

Answer 25

Groovy, 9 bytes

{print{}}

Outputs:

Script1$_run_closure1@2c8ec01c

Because it outputs the memory address of the closure it is non-deterministic.

Answer 26

PHP, 12 bytes

<?=uniqid();

Outputs a unique ID 583f4da627ee3 based on the current time in microseconds. ↑

Answer 27

Borland C on Windows, 12 bytes

m(){puts();}

I rewrote it because they say is possible to use one function. Compiler has not check the argument so compile it; but puts see one address 'nobody' know and begin to print what point that address until find the byte 0x00. It could be not ok if that address is out of memory reserved to program but here print something

Answer 28

C89 with GCC/Clang, 20 bytes

The other C solution just segfaults every time when built with GCC or Clang. This, though.

main(n){puts(&n+1);}

Which looks like:

$ for _ in `seq 1 50`; do ./test_89; done
���z�U
�VW��U
�F��U
�v�f2V
��FV
���*=V
�6���U
�20wU
��
�+V
�6
   �U
��V�uU
�v��V
���K�U
��7�qU
�6S�jU
�&�WU
��wV
��6l�U
���U
�F�ߨU
�f���U
���s7V
�f��?V
��;B�U
�;��U
��GV
�� ��U
�vKV
�V?]wU
�����U
��.�U
�v"�XU
��uhpU
��LD�U
�����U
�6X�U
��M�.V
�69��U
��ԤV
���U
����U
�vx4.V
�֝+xU
�F��U
�֤BQV
��#�U
���1^U
����sU
��4�U
��AݗU

Quite a lot of unprintable junk but it's nondeterministic!

Answer 29

Emotinomicon, 15 bytes

⏬

Explanation:

⏬
      push 0. Stack: [0]
      push 1. Stack: [1]
      random[pop;pop]. Stack: [1 or 0]
      ⏬output

Answer 30

Baby Language, 0 bytes

I didn't submit this originally because I thought it postdated the question. I was wrong; the language did have an interpreter created in time. It's also probably the least cheaty 0-byte solution I've seen (given that a 0-byte program is specified to do exactly what the program asks, and not for the purpose of cheating on golfing challenges).

Baby Language is specified to ignore the program it's given and do something at random. (The interpreter linked on the Esolang page generates a random legal BF program and runs it.) That seems like a perfect fit for this challenge.

Answer 31

Jelly, 2 bytes

9X

Idk if this works. I've never done anything in jelly before, and I'm on my phone right now.

Int from 0 to 9.

Answer 32

><>, 4 3 bytes

(crossed out 4 still looks like 4)

0nx

Try It Online!

Outputs some amount of 0's.

On an empty stack n throws an error and terminates the program. x chooses a random direction for the stack pointer. This means that for each 0 printed, there is a 50% chance for the program to exit.

Answer 33

Japt, 1 byte

Ð

Test it online!

How it works

When Japt is compiled to JavaScript, it replaces Ð with new Date(. The close-paren is automatically added by the interpreter, and the result of the last expression is automatically printed, so this prints the current date/time.

An alternate solution would be Mr, which uses Math.random. Japt also has the variable K set to Date (no clue why I did that, it's almost entirely useless), which I guess makes K a valid function entry.

Answer 34

Mathematica, 6 bytes

Date[]

Pretty self-explanatory. (This function was superseded by DateList[] in later versions, but Date[] still runs.)

For 8 bytes one can also use Random[] (itself a legacy function).

Answer 35

MATL, 1 byte

r

Uniform random number generator between 0 and 1. The seed is randomly set for each execution of the program. Try it online!

Answer 36

C#, 36 22 bytes

a=()=>a.GetHashCode();

Yay.

Answer 37

C++, 26 19 Bytes

std::cout<<new int;

Returns a different memory address each time it's run

Answer 38

Cubix, 3 bytes (non-competing)

@OD

Outputs a random positive number of zeroes. Non-competing because I added D just a few minutes ago. Before it was added, there was absolutely no way to randomize anything in Cubix.

Test it online!

How it works

Before the code is run, it's padded with no-ops . and formed into a cube net. Here's what the net for this particular program looks like:

  @
O D . .
  .

Now the code is run, starting on the left-most face and heading to the right.

First, O outputs the top item on the stack as a number. At the beginning of the program, the stack is an infinite fount of zeroes, so this prints 0.

Next, D sends the IP (instruction pointer) in a random direction: possibly up to the @ which ends the program, and possibly back to the O which prints another 0. This continues until whenever the IP hits the @.

@DO and OD@ also work, each printing zero or more zeroes.

Answer 39

x86/amd64 machine language (Pentium or higher), 3 bytes

0:       0f 31                   rdtsc  
2:       c3                      retq

This uses the RDTSC instruction that may not be available on older processors. To test, try the following C program on Linux x86/amd64

#include <stdio.h>
int main(){
  for( int i = 0; i < 10; i++ ) {
    printf( "%d\n", ((int(*)())"\x0f\x31\xc3")() );
  }
}

Or try it on Ideone.

Answer 40

Minecraft, 2 bytes

/r

Must be written into chat when playing on multiplayer servers. Will throw an error if you hadn't messaged (/tell) anybody recently. Otherwise, shows both players a random message.

Note: I'm not really sure if this is a legit solution :)

Minecraft, 4 bytes (+2 blocks)

help

Ties with another Minecraft answer from @Pavel

This is based on Minecraft's Easter egg:

When you type help or /help in a Command block, a random message starting with "Searge says:" is displayed, for example "Searge says: Ask for help on twitter". Here is a full list of messages.

Answer 41

Lua, 9 bytes

print({})

Outputs the internal address of the Lua table object:

table: 0x2370ab0

If you're running from the interactive interpreter, you can use just 3 bytes:

> ={}
table: 0x23719c0

Answer 42

C, 19

f(a,b){putchar(b);}

In C the second declared variable in a function's arguments is random based on memory. Assuming the arguments were not actually declared, i.e. you just called f();.

So this function can be simply called with no input-arguments. That is, just: f(); and the output will be a random character.

Try it online! (Note: output might be an unprintable character, run the program a few times to see variation, you should get more printable characters than non-printable characters)

Answer 43

C (gcc), 18 bytes

f(){printf("%d");}

This one may be difficult to test since TIO will give you a cache hit. Just add some whitespace and try it again.

Try it online!

Answer 44

INTERCAL, 0 2 bytes (0+2 for command flag)

Try it online! (I don't know if the TiO compiler reproduces this functionality correctly)

This is not a valid INTERCAL program, so attempting to run it gives Error 778 - UNEXPLAINED COMPILER BUG. However, when INTERCAL is run without the -b command flag, there is a small chance that it doesn't run and throws Error 774 - RANDOM COMPILER BUG. So if errors count as output for this challenge, then INTERCAL might actually be good for something!

INTERCAL, 17 bytes

DO %9 READ OUT #5

Try it online!

This is a more standard approach. It has 9% chance of printing V before terminating (with an error, but it gives the output, so who cares?)

Answer 45

Retina, 3 bytes

?&`

Try it online!

Yay, Retina can finally compete in challenges that require randomness! \o/

Explanation

?& is a compound stage which executes its child stage with a 50% probability. That child stage is itself a Count stage, which counts the number of empty matches in the empty input (1). So if the child stage is run, the result is 1, if it isn't, then the empty input remains unchanged and we get an empty string.

A fun alternative for the same byte count would be:

?+`

Try it online!

This one uses a random loop (which uses a coin toss before each iteration to decide whether to continue). This one has a 50% chance of printing an empty string, 25% of printing 1 (one iteration) and a 25% chance of printing 2 (two or more iterations).

Answer 46

Lost, 7 bytes

@%"
///

Try it online!

Since Lost starts the pointer in a random place facing a random direction, it's refreshing not making the output deterministic for once. I think this is the optimal solution since you need the @ and % in order to end the program, the " to push stuff to the stack at random, and the /// to avoid infinite loops.

Answer 47

Kotlin script (.kts), 12 bytes

print(Any())

Any is a compile-time time wrapper for Object, default toString() of any object is class name@hashcode. Probably the shortest solution that runs on the JVM.

If .kts is cheating:

18 bytes: fun a()="${Any()}" (forgot functions are a valid answer)

38 bytes: fun main(a:Array<String>)=print(Any())

Answer 48

PHP, 10 Byte

<?=time();

This prints the current Unix time which – of course – isn't random but changes when you call the program several times. The output I just got is 1480548602.

Answer 49

APL, 2 bytes

?9

This uses APL's roll (?) operator. The program prints a pseudo-random number between 1 and 9.

Answer 50

Brachylog, 3 bytes

9$?

Try it online!

Explanation

$? is the random number predicate. When given an integer as input (here, 9), its output will be unified with an integer between 0 and 9 uniformely at random.

Answer 51

Randwork, 11 bytes

Uses the Randwork+ instruction set, because that's the only specification with an existing interpreter.

Do anything

This statement executes a random instruction from the instruction set. There is a 7/28 (25%) chance of non-empty output. I calculated the probability by viewing the source code of the interpreter. The instructions that can produce output are:

Write the ASCII equivalence of a random byte
Beep
Write the ASCII equivalence of byte 1
Write the ASCII equivalence of byte 2
Write the ASCII equivalence of byte 3
Write the ASCII equivalence of byte 4
Display the Hello World message

Bytes 1-4 have not been set, so output of any of them will be a NUL byte. The 7 possibilities of non-empty output are (in corresponding order):

\x?? - a random byte
\x07 - the bell character (beep)
\x00 - NUL
\x00
\x00
\x00
Hello world

Answer 52

PHP 10 bytes

<?=rand();

Prints a random number between 0 and getrandmax(). Which may vary based on what computer it's run on.

Answer 53

Java2K, 9 bytes

I don't recommend trying to write an approximation of a deterministic program in this language.

11 6/*/_\

This function has a 90% chance to return 1, otherwise it will return a random number. 11 6 is the name of the division function. A function is called like <name>/<arg0>/<arg1>\. Basicaly every function returns the "correct" result 90% of the time, or else a random number.

The token * is replaced by a random number, say 203. The _ token is replaced by the previous argument, i.e. 203. So, this function will divide 203 by 203 which has (see below) a 90% chance of returning 1.

Answer 54

TI-83 Hex Assembly, 4 bytes

PROGRAM:ND
:AsmPrgm
:EF0A45
:C9

Run it with Asm(PrgmND). Calls the _PutS system library call (0x450a), but because it doesn't set HL it will print whatever HL pointed to last, usually a lot of garbage text.

I count this as 4 bytes, because each pair of hex digits is one byte.

Answer 55

CJam, 2 bytes

et

• You can rely on the program being run at a different (unknown) time each execution.

Yeah, that one. et is a single built-in that returns the array [YYYY M D h m s ms W Z], printed as YYYYMDhmsmsWZ.

Answer 56

Ruby, 14 bytes

p ?..object_id

Returns object id of the string '.'

Answer 57

TI-Basic, 2 bytes

Very similar to this answer. The getTime token is two bytes and is located at EF 0A.

getTime

Answer 58

C#, 72 bytes

It's alot longer than the other C# answer but hey, different approach and fully functioning console application. Why not?

Golfed

using System;class P{static void Main(){Console.Write(Guid.NewGuid());}}

Ungolfed

using System;
class P
{
    static void Main()
    {
        Console.Write(Guid.NewGuid()); //Create a new random GUID and print it
    } 
}

Answer 59

BrainFlump, 5 bytes

:+:;.

Try it online!

Outputs either a NUL or SOH character

Explanation

BrainFlump is the latest iteration of BrainFl* languages having different memory models (BrainFlak is a stack, BrainFlueue is a queue, etc)

In BrainFlump, memory consists of a Cell and a Dump.

The Cell is a single numerical value, and the Dump is an unordered collection of numerical values.

When the program starts, the Dump is empty, and the Cell is 0.

:      Push the Cell's value to the Dump
 +     Increment the Cell
  :    Push the Cell's value to the Dump
   ;   Pop a value from the Dump (randomly) to the Cell
    .  Print the Cell's value as an ASCII character
       The Cell's value will either be 0 or 1, and as it's printed as an
       ASCII character, this results in NUL or SOH

Answer 60

Wumpus, 4 bytes

UFO@

Try it online!

Outputs a uniformly random choice of 2, 5 or 8.

Explanation

Apart from a regular stack, Wumpus also has 20 registers which are arranged around the faces of an icosahedron. You can imagine the icosahedron as a d20 resting on a table: the face touching the table is the "active" face (i.e. the register that can currently be interacted with). Also, every face has an index from 1 to 20. Initially, the active face is 1 and the three adjacent faces are 2, 5 and 8 (see the README in the Wumpus repo for the full net).

U   Randomly tip the icosahedron onto one of the three adjacent faces, i.e.
    change the active faces to either 2, 5 or 8.
F   Push the index of the currently active face.
O   Output as a decimal integer.
@   Terminate the program.

Alternatively:

DFO@

This one completely randomises the orientation of the icosahedron, so it prints a random number from 1 to 20, inclusive.

Answer 61

Intercept 1.1, 37 bytes

Prints newlines to the terminal. You'll probably have to leave this one overnight, as there is a delay of 5-15 minutes (it's random!) between each newline. Note that while you can determine what is being printed, you can't determine how often it's being printed.

Input is marked with a >>. The command prompt is the empty >>.

Assuming a system with only TZ_INFECT installed...

>> malware bm bitminer
creating bm (bitminer)
... wait a minute ...

finished creating bm (bitminer)
>> software install 1
Success
bm installed

...wait...
(newlines)








>>

Note that I'm using a custom client that prefixes [BROADCAST] to all broadcast events.

How???

TZ_INFECT is Intercept's malware generator. We can generate a bitminer by running malware <name> bitminer. This will create a new piece of software with the given name of type bitminer

We then install the bitminer: software install <index>, where index is the 0-based index of the software as given by software list. This is why I made sure the only piece of software on the system was the malware generator. This places our new bitminer at index 1.

There is a bug in the implementation of bitminer that results in an empty broadcast event to be sent to the client whenever bits are generated. Since bits are generated at random intervals, the broadcasts are sent at random intervals. Voilia, non-deterministic output!

Note: the newlines are harder to detect using the official game client, but you can see them by running a command and watching the newlines slowly push the resulting output off the screen.

Screenshots coming in a few hours while I wait for the output.
After 20 minutes (the [BROADCAST] is a newline):

After 2 days:

Answer 62

Keg, 1 byte

~

This pushes a random number onto the stack and then outputs that number by default.

Answer 63

Wirefunge - 2 bytes

¿>

¿ - Randomized output every iteration

> - When it rises, puts 1-8 on stdout

Answer 64

Clojure, 4 bytes

rand

The obvious answer. rand is a core function that returns a floating-point number between 0 and 1 (exclusive) when called without any arguments.

I don't think it gets any shorter than this in Clojure.

Answer 65

Perl 6, 13 bytes

put Bool.pick

Answer 66

Swift 3, 13 bytes

print(Date())

Answer 67

Marbelous, 5 bytes

FF
??

Prints a single random byte. FF creates a marble with value 255. That marble falls through the random number generator ?? which replaces the marble's value with a random value between 0 and 255 inclusive. When the marble falls off the bottom of the board, it gets printed to STDOUT as a byte.

Answer 68

R, 7 bytes

The Student t Distribution

rt(1,1)

The Exponential Distribution

rexp(1)

Two options how to generate a random number with the shortest code.

Answer 69

ForceLang, 11 bytes

random.rand

A function that, when called with no arguments, produces a random rational of the form n/2^80, where n is an integer on [0,2^80-1].

(If you give it a positive integer argument m [which must be strictly less than 65536, not that you'll ever reasonably need to go nearly that high] it will produce a random rational of the form n/2^m, where n is an integer on[0,2^m-1])

Answer 70

Thue, 17 bytes

a::=
a::=~1
::=
a

Randomly prints either nothing, or the digit 1.

Answer 71

T-SQL 15 bytes

print getdate()

Answer 72

Minkolang v1.5, 4 bytes

lhN.

l pushes 10. h pushes a random integer from 0 to 10, N outputs it and . ends program. Simple, eh?

Try it online!

Answer 73

Ceylon (on JVM), 22 bytes

()=>system.nanoseconds

This turned out surprisingly difficult. At first I thought I cold use the .hash attribute of all objects (corresponds to Java's .hashCode() when running in the JVM), but it turns out that most objects I can write in a literal way have their .hash attribute overridden, returning a deterministic value.

For example, [] (the empty tuple) or {} (the empty iterable) are both the same object, and which inherits List.hash, which returns 1 in this case. For strings (like ""), characters (c) or numbers (like 3 or 2.5) of course the hash needs to be deterministic, same for true and false (0, 99, 3, 1074003968, 1231, 1237, respectively).

The base class Basic, which has the Java-like hash code implementation (assumedly based on the memory address?) is abstract, so I can't use Basic().hash (nor Object().hash – also abstract, and here even the method is not implemented). So let's create a new class, create an instance and take its hash code?

class E() {}
function f() => E().hash;
shared void run() {
    print(f());
}

This always outputs 1116094714 whenever I execute this program. (Adding other statements which allocate memory before the print line changes the result – still deterministically, though.)

Ceylon also supports anonymous classes as object expressions. Those can extend classes or implement interfaces and have own code, but the most minimal variant is just object{}:

shared void run() {
    function f() => object{}.hash;
    print(f());
}

Still the same result 1116094714, though.

Another idea was to use the hash code of a class or function reference. (Those are normal objects, I thought.) But trying to use run.hash (or f.hash) gives a compiler error:

error: direct function references do not have members

We can work around this by assigning this function reference first to a value, which will create an object of a (hidden) anonymous class:

shared void run() {
    value x = run;
    value y = run;
    print([x.hash, y.hash]);
}

This prints two different values, but the same ones ([762384154, 690052870]) each time I run the program. Still deterministic.

So, using any hash code will not bring us forward (and I suppose that the other JVM answers here with .hashCode() would have the same problem on my JVM implementation). Same with printing an object with the default .string implementation based on .hash.

There is no random number facility in ceylon.language, so using either ceylon.random or Java's java.util.Random (or java.lang.Math.random()) needs an import, which increases the size more than I want to tolerate for a codegolf answer. Here is an example:

import ceylon.random { ... }
shared void run() {
    print(randomize{1,2});
}

So let's look at what we have in ceylon.language. There are four top-level objects which allow access to the environment:

• operatingSystem – name, version, path/file separator, newline.
• process – command line arguments, system properties, environment variables, input/output.
• runtime – whether we are on JVM/JS/Dart, version info, and stuff like bit sizes. Nothing which will change between runs of the same program in the same VM.
• system – ah, here we go. Beside locale, character encoding and time zone offset we also have:
  • milliseconds
  • nanoseconds

Both will change with each call of a program, and the latter one is shorter.

So here we have an anonymous function returning different values:

() => system.nanoseconds

If we want a named function, its definition can look like this:

Object n()=>system.nanoseconds;

(It actually returns Integer, but that is one character longer than Object.)

Answer 74

Shell, 2 bytes

ps

Explain: the PIDs returned are not going to be the same each time.

Answer 75

SmileBASIC, 6 bytes

?TIME$

Prints the current time.

Answer 76

tcl, 3

Must be run on an interactive shell

pwd

Gets the current working directory.

Or alternatively

pid

Gets the current process identifier

Demo: Go to https://www.tutorialspoint.com/execute_tcl_online.php and in the green area, type

tclsh

Then type

pwd

and

pid

Answer 77

Alice, 4 bytes

2Uo@

Try it online!

Prints a single byte, either 0x00 or 0x01, with 50% probability each.

2    Push 2.
U    Get a random integer in [0,1].
o    Output that integer as a byte.
@    Terminate the program.

Answer 78

Fourier, 3 bytes

9ro

Outputs a random number from 0 to 9.

Try it online!

Answer 79

Braingolf, 2 bytes

1r

Pushes 1 to the stack, then pushes a random number between 0 and the last item on the stack (1). Implicitly prints the last item on the stack (the random number)

Answer 80

Add++, 6 bytes

The most random I could get for 6 bytes

+9  Set the accumulator to 9
R   Set the accumulator to a random integer between 0 and 9
O   Output the result

I could change R to R-9 to double the randomness for 2 extra bytes.

Answer 81

Taxi, 224 222 bytes

Go to Heisenberg's: w 1 r, 3 r, 1 l.Pickup a passenger going to The Babelfishery.Go to The Babelfishery: s 1 r, 1 l.Pickup a passenger going to Post Office.Go to Post Office: n, 1 l, 1 r.Go to Taxi Garage: n 1 r, 1 l, 1 r.

Prints a random number. The spec does not give any details on what number should be. The last statement can be omitted if you don't mind the code giving an error after printing the output.

Answer 82

Chip, 2 + 3 = 5 bytes

+3 bytes for -w

g?

Gives infinite-length output. Each byte of output is independent, and is either NUL \x00 or '@' \x40.

There are eight equivalent Chip programs that are like this, from a? (which prints \x00 or \x01) to h? (which prints \x00 or \x80). g? is just the most visible option.

For each of these programs, the letter a through h defines the index of a bit of the output, and ? produces a random value to set it to. The two elements may be provided in any order; they must only touch each other on a 2D plane.

Try it online! The TIO includes the -cN flag. This flag is not necessary, but cuts off the program after N bytes. Try without the cutoff if you wish, but TIO's limit is at 128KiB.

Answer 83

Rust, 28 bytes

fn main(){print!("{:p}",&1)}

Try it online!

Takes a reference to a temporary 1 and prints the address.

---

Rust, 17 bytes

fn main(){0-1u8;}

Try it online! (requires the -A const_err compiler flag)

This is a bit sketchier, and I'm not sure whether it counts. The non-deterministic output is to STDERR, and the non-determinism arises only based on the value of an environment variable.

This program attempts to compute 0 - 1, where both integers have type u8 (the default is i32, which won't cause an overflow because it's signed). By default, Rust compiles the file in debug mode, in which arithmetic overflow causes a panic instead of wrapping. When a program panics, it will print a stack trace if the environment variable RUST_BACKTRACE is set to 1, hence the non-determinism.

Answer 84

Flobnar, 5 4 bytes

^{-1 byte thanks to @JoKing}

0?.@

Try it online!

Answer 85

Ink, 5 bytes

{~a|}

Try it online!

Either outputs "a" or nothing.

Answer 86

Perl 6, 7 bytes

say now

about now

Answer 87

Japt, 1 byte

K

Try it online!

Answer 88

Trigger, 14 bytes

ABAAA AAB    B

Try it online!

A                NOT the value of the A trigger, making it one
 B               NOT B
  AAA            Print "A"
      AAB        Go to the nearest B in the program. If it is the same distance, it picks it randomly. This can go to the NOT B command or go to the next B command, running the print A or ending the program, respectively.

Answer 89

Shellscript (as implemented by ttyrec), 0 bytes

OK, here's a version of this idea that uses an interpreter that can actually be programmed with.

The ttyrec command by default just passes everything it sees on standard input to a shell, and thus obeys our definition of a programming language (it's Turing-complete, because bash is; it's basically just an alternate front-end to bash, and so is basically a shellscript interpreter that can be used to program with). However, it also creates a file ttyrecord containing a recording of the shell's output, and that file starts with the current time, in binary (and is also affected in some ways by the system's CPU and swapping load, as it tries to separate the output into frames). Thus, it produces a file with nondeterministic content as output.

Answer 90

JavaScript, 8 bytes

Date.now

This evaluates to a function whose return value is nondeterministic, and conveniently doesn't actually need to be bound to anything specific to work.

Answer 91

Batch, 6 4 bytes

time

Needs to be run with <nul which is apparently permissible.

Answer 92

QBIC, 4 bytes

?_r|

This generates and prints a random number between 0 and 10. QBIC uses the classical RANDOMIZE TIMER at the start of execution to set the RNG.

Answer 93

Actually, 1 byte

G

Try it online!

Good old rand(). In Python 3, 2500 random bits from the system's cryptographically-secure randomness source (getrandom() for Linux, /dev/urandom for *NIX, or CryptGenRandom for Windows) are used for the seed, falling back on the current UNIX time (as precisely as possible for the given platform - at minimum, 1-second precision) if such a source of randomness is not available.

Answer 94

Microscript II, 1 byte

R

Produces a random 64-bit float on [0,1).

Another one-byte solution would be C, which produces a new continuation object, whose timestamp (which the reference implementation includes in its string representation) will be nondeterministic.

Answer 95

Microscript, 2 bytes

r9

Produces a random integer on [0,8]

Answer 96

Mouse2002, 7 bytes

&RAND !

Answer 97

ASP VBScript, 43 bytes

<%=createobject("scriptlet.typelib").guid%>

Outputs a unique ID like {52076580-3151-4EE7-AAFD-D975CD141EE4} based on current date/time. ↑

Answer 98

HSPAL, 18 bytes

26FFFF
400000
120000

Prints a random 16-bit integer.

Answer 99

Math++, 5 bytes

$rand

Produces a random 64-bit float

Answer 100

C, 22 bytes

f(){putchar(time(0));}

Answer 101

Chip-8, 4 bytes

0xCFFF 'RND vF,FF
0xFF18 'LD ST,vF

This plays a sound for between 0 and 4.25 seconds. The seed always starts at 0, but it updates during the display interrupt which has a tiny chance of happening before the randomizer call, I hope.

Answer 102

Pyt, 1 byte

ɽ

Returns a random 32-bit integer.

Also 1 byte: ɹ, ṛ.

Answer 103

Gol><>, 3 bytes

x1h

The 'x' is a randomizer for the direction of the pointer, the 1 pushes a 1, and the h outputs and halts.

Try it online!