10 PRINT CHR$(205.5+RND(1)); : GOTO 10 in PHP (or anything else, for that matter)

Question

Just had a 'spirited' conversation with a co-worker about the succinctness of the following BASIC statement:

10 PRINT CHR$(205.5+RND(1)); : GOTO 10

It's the title of this book, and will simply print a sequence of / and \ characters, alternating between the two randomly, resulting in a pattern similar to this:

(Image borrowed from http://www.flickr.com/photos/rndmcnlly/5058442151/sizes/o/in/photostream/)

Being of a PHP proclivity, we wondered what the most compact way of writing the same thing in PHP would be, and came up with this:

while(1) { echo chr(47 + 45 * rand(0,1)); }

chr(47) is a / character, and chr(92) is a \. So the statement echo chr(47 + 45 * rand(0,1)); will randomly alternate between the two, ad nauseam.

In a language of your choosing, write the shortest program or function to output an infinite random sequence of \ and / characters, where each character has an equal probability of being chosen.

Answer 1

Python, 61 bytes

from random import*
while 1:print('/\\'[randint(0,1)],end='')

Pretty self explanatory. Had to use the double backslash since backslashes are escape characters in Python.

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Answer 2

R, 33

Just interested to see whether this can be made smaller.

while(1)cat(sample(c('/','\\'),1))

Answer 3

JavaScript (Node.js), 59 55 54 bytes

Original Answer

while(1){process.stdout.write(Math.random()>=0.5?"/":"\\")}

-4 bytes thanks to manatwork

while(1)process.stdout.write(Math.random()<.5?"/":"\\")

-1 byte thanks to Conor O'Brien

for(;;)process.stdout.write(Math.random()<.5?"/":"\\")

Answer 4

BRASCA, 13 12 bytes

1[`/\`1?#$o]

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Explanation

1[         ]  - While 1:
  `/\`       -   Push \ and /
      1?      -   Push rand(0,1)
        #$    -   If truthy, swap the top two items, else skip.
          o   -   Print it!

Answer 5

Add++, 19 bytes

D,f,,"\/"BX
Dx,$f,o

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How it works

D,f,,    ; Define a function, f
    "\/" ; Push "\/"
    BX   ; Random choice

Dx,      ; Do, while x:
   $f,   ; Set x to the result of f
   o     ; Output with no newline

Answer 6

Python 3, 52 51 bytes

from random import*
while 1:print(end=choice('\/'))

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Saves at least 9 bytes over other python solutions here.

Edit: saved a byte via ayreguitar's comment

Answer 7

I guess you can use recursion.

function slashes() {echo chr(47 + 45 * rand(0,1)); slashes();}

---

I guess you can use recursion.

function slashes() {echo chr(47 + 45 * rand(0,1)); slashes();}

---

...

Answer 8

chopped off one character:

while(1) { echo chr(2 + 45 * rand(1,2)); }

then remove the curly braces:

while(1) echo chr(2+45*rand(1,2));

another trick, with the same length:

while(1) echo chr(rand()%2*45+47);

Answer 9

Perl

This one looks funny for me :

perl -pe '$_="~"ge$_?"/":"\\"' </dev/urandom

(Sorry to be out of subject here. I know this is not PHP)

Answer 10

Powershell, 37 bytes

for(){Write-Host(Random("\","/"))-N}

unfortunately there seem to be no shorter aliases for Write-Host that don't cause a new line after every char.

Answer 11

Fission, 12 bytes

[#"\"R
W\"/"

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Answer 12

Tcl, 53 bytes

while 1 {puts -nonewline [expr rand()<.5?"/":"\\\\"]}

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Answer 13

Perl 6, 23 bytes

loop {<\ />.pick.print}

• loop loops forever.
• <\ /> is a list of the strings \ and /.
• .pick picks one of the two strings randomly.
• .print prints that random string.

Answer 14

Pyth - 12 9 bytes

#@,\/\\O2

Tested without loop code because the online interpreter dislikes infinite loops

Explanation:

#@,\/\\O2
#             Repeat until Error
 @            Implicitly print item number
       O2     random number between zero and two exclusive
  ,           of two item list containing
   \/         One character string /
     \\       One character string \

Answer 15

Add++, 24 bytes

+1
W,R2,-1,*45,+47,H,x:1

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Answer 16

q/kdb+, 18 bytes

Solution:

while[1;1"\\/"1?2]

Explanation:

A simple while(true) loop...

while[1;1"\\/"1?2] / the solution
while[1;         ] / while true do ...
              1?2  / 1 choose 2 (0 or 1)
         "\\/"     / string \/, index in at 0 or 1
        1          / print to stdout without newline

Extras:

Another 18 byte solution: {1"\\/"1?2}\[::;1]

Answer 17

Japt, 9 bytes

iOo"/\\"ö

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Answer 18

MathGolf, 8 bytes

1Æû\/wq∟

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Explanation

1          push 1
 Æ     ∟   do-while-true without popping using 5 operators
  û\/      push "\/"
     w     random char from string
      q    print without newline

Implicit popping doesn't seem to be working as intended when using do-while-true, or any other loop type. With this working correctly, the first 1 could be removed.

For a "working" 7-byter, you could do t{û\/wq, which replaces the do-while-true with a simple for loop, and begins the script by pushing the current timestamp in milliseconds to the stack. Currently, that means about \$1.56*10^{12}\$ iterations, which is "infinite" for most applications. However, this is not a valid answer, so the official answer is still 8 bytes.

Answer 19

APL (Dyalog Unicode), 12 bytes

→≢⍞←'/\'[?2]

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Tradfn body that prints indefinitely.

Thanks to @Adám for 5 bytes, and for pointing out that, with a little bit of CSS magic, TIO can print the actual pattern like in the image.

How:

→≢⍞←'/\'[?2] ⍝ Tradfn body
         ?2  ⍝ Roll (randomly select) an integer between 1 and 2
        [  ] ⍝ Use the result to index...
    '/\'     ⍝ ...the string containing the two slashes
  ⍞←         ⍝ Print it to the same line
 ≢           ⍝ Tally the result (yields 1)
→            ⍝ then 'goto' that line

Answer 20

Runic Enchantments, 13 bytes

`/-R`A*+k$!;

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Slightly ungolfed for readability, with spaces to separate operational segments:

'/  2'RA  '- *+k $ !;

The difference of 45 is encoded in the - char literal, as chars are implicitly converted to integers when fed into a operator expecting a number value.

2'RA randomly generates a 0 or a 1, multiplied against the - and added to the / char resulting in either / or \, which is then printed after being coerced back to a char from an int. In the golfed version the  (0x02) serves as the 2.

Then the program loops forever by skipping the terminator, !;.

Answer 21

><>, 12 bytes

x!\"/!
^o< <

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The idea here is to use x in combination with the ^ below to both loop and choose a random horizontal direction. If the IP goes left from the x, it will skip the mirror / and quote the string "\!x!/", reflect upwards with \, wrapping around to the <, which redirects the IP to output the result and begin the loop again. If the IP goes right from the x, a similar thing will happen.

This is all thanks to the nice happenstance that / and \ are control flow modifiers in ><>, allowing us to save a ".

An alternative solution for 13 bytes is slightly more generic and generates a lot fewer side effects.

xa!o"/\"o!a
^

(You can replace the as with spaces; I have them placed here for clarity. In production code, you would want to do this replacement to avoid unnecessary stack population.)

Answer 22

Clojure, 34 bytes

(loop[](pr(rand-nth"\\/"))(recur))

Answer 23

Zsh, 42 bytes

for ((;;))printf ${(#)$((RANDOM%2?47:92))}

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Answer 24

AppleSoft BASIC, 33 bytes

33 bytes, verified here

1?MID$("\/",RND(1)+1.5,1);:GOTO1

35 bytes, using CHR$ conversion similar to C64.

1?chr$(47+45*int(2*rnd(1)));:goto1

Answer 25

Factor + qw, 33 bytes

[ qw{ / \ } random write t ] loop

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Answer 26

Lua 5.4, 49 bytes

::a::io.write(2>math.random(2)and"\\"or"/")goto a

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Answer 27

Yabasic, 27 bytes

-1 byte thanks to @ayreguitar

Mid$("\/",...) is used over Chr$() as the character codes for / and \ are 47 and 92, respectively.

While the GoTo structure of the original could easily be used for this yabasic answer, Do...Loop ends up being shorter due to the the structure of the Mid$ call.

Do?Mid$("\/",Ran(3),1);Loop

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Answer 28

Go, 78 bytes (fixed seed)

package main
import."math/rand"
func main(){for{print(string(`/\`[Intn(2)]))}}

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Prints to STDERR.

Random seed, 107 bytes

package main
import(."math/rand";."time")
func main(){Seed(Now().Unix())
for{print(string(`/\`[Intn(2)]))}}

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Also prints to STDERR.

Answer 29

Mathematica - 36 Bytes

Barebones with no formatting. I don't know why the slashes are different thickness

Grid@RandomChoice[{"/","\\"},5{8,5}]

Answer 30

Python, 66 bytes

import random
while 1:print(chr(47+random.randint(0,1)*45),end='')

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Ungolfed:

import random
while True:
    slash_calc = 47 + random.randint(0, 1) * 45
    print(chr(slash_calc), end='')