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

JavaScript (full program), 12 bytes

throw is much smaller than console.log() or process.stdout.write(), it does halt execution, but that's not an issue.

throw Date()

Answer 2

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 3

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 4

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 5

Ruby, 14 bytes

p ?..object_id

Returns object id of the string '.'

Answer 6

TI-Basic, 2 bytes

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

getTime

Answer 7

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 8

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 9

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 10

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 11

Keg, 1 byte

~

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

Answer 12

Braingolf, 2 bytes

2r

Pushes 2 to the stack, then pushes a random number between 0 and the last item on the stack (2), ie randomly selects either 0 or 1. Implicitly prints the last item on the stack (the random number)

Answer 13

><> (Fish), 4 bytes

1n0x

Try it

Prints 1, then prints 0 or 1 randomly, as the x will cause the instruction pointer to move either left or right.

Answer 14

Uiua, 1 byte

⚂

Try it!

Prints a random float from 0 to 1 each time the program is run.

Answer 15

C (gcc), 24 bytes

main(){printf("%s",.0);}

My favourite, since the warning messages in stderr also get corrupted slightly.

Try it online!

Answer 16

Wirefunge - 2 bytes

¿>

¿ - Randomized output every iteration

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

Answer 17

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 18

Perl 6, 13 bytes

put Bool.pick

Answer 19

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 20

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 21

Thue, 17 bytes

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

Randomly prints either nothing, or the digit 1.

Answer 22

T-SQL 15 bytes

print getdate()

Answer 23

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 24

Shell, 2 bytes

ps

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

Answer 25

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 26

SmileBASIC, 6 bytes

?TIME$

Prints the current time.

Answer 27

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 28

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 29

Fourier, 3 bytes

9ro

Outputs a random number from 0 to 9.

Try it online!

Answer 30

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.