0221: "Random Number"

[Andrew]

There was a Dilbert strip on this theme a long time ago.

Dilbert is touring the Marketing Department.

Marketing Guy: (Points to Guy in Chair) This is our Random Number Generator.

Guy in Chair: Six, six, six, six, six...

Dilbert: That doesn't seem very random.

Marketing Guy: How do you know it isn't?

Would you know where I can get a copy of this? It'd be useful for illustrating a point on my website.

[Ronfar]

Dilbert's random number generator, courtesy of web.archive.org:

http://web.archive.org/web/20011027002011/http://dilbert.com/comics/dilbert/archive/images/dilbert2001182781025.gif

[william]

I love the way you compared his emails to hitler's moustache.

[JamesF1]

Let's take this a step further... to an A86 function:

Code: Select all

RandN:
  SUB AX,AX
  MOV AX,4
  RET

To be fair, there's no simple way to return the value in A86... could have pushed it to the stack... but that's not a lot of use, as we have to pop the IP (Instruction Pointer) back off the stack to continue program execution after the function... so that's largely redundant as we'd have to pop off the return value first...

If in doubt, use AX

Seeing that brings back memories.
SUB register, register is the fastest way to zero in x86 which is kinda weird.
Also why did you zero the register before moving 4 into it, I don't remember that being one of the x86 "trickses".

Simply because if you'd used AX outside of the function, regardless of whether this is a near or far execution, AX would still have a value in it. As 4 will be represented as a value just in AH (due to byte swapping), you could end up with a residual value in AL.... zeroing AX beforehand ensures you don't end up with any stupid results from left-over register data.

[EvanED]

SUB register, register is the fastest way to zero in x86 which is kinda weird.

I thought that was XOR reg, reg...

P4 takes one cycle to subtract and one cycle to XOR if the instruction's scheduled on one of the fast ALUs. (Well, okay, a second cycle to set the flags.)

I don't know the Core architecture or previous to the P4, or other vendor's.

[SpitValve]

Nope, not f77. That "end function random", and the use of lower case, makes it Fortran 90 at the very earliest. Fixed form source, but still Fortran 90.

Well, it's f77, but with a modern compiler which allows a bit of f90 leeway...

Having said that - good grief, another Fortran programmer! I am not alone

w00t! You doing physicsy stuff too?

[kakos]

Code: Select all

++++.

Firstly, I had brainfuck code back on page 1, and secondly, that prints out a Ctrl-D, which is probably not what you want.

The code to print out '4' is:

Code: Select all

++++++++++++++++++++++++++++++++++++++++++++++++++++.

To return 4, it's

Code: Select all

++++

as I had before.

Ah, right. Thanks. My brainfuck-fu is weak.

[kakos]

I'll add some lambda calculus to the mix.

Code: Select all

λf.λx. f (f (f (f x)))

[Andrew]

Dilbert's random number generator, courtesy of web.archive.org:

I love the way you compared his emails to hitler's moustache.

I thank you both.

Edit: how on Earth did you find that?

[warriorness]

Code: Select all

"chosen by fair dice roll.
"guaranteed to be random.
Disp(4

Disp( Reminds me of my Ti-83, but I don't know if there were comments. So probably not.

Putting a String on its own line with nothing else counts as a comment. Either that, or it prints the string... I don't remember

The above one is TI-BASIC.

But only for calculators related to the TI-83 and -85. Not the -89 line which requires all parentheses be closed.

Leaving hanging parentheses, quotes, etc is the best and easiest way to save memory on your programs. I used to write games in TI-BASIC, and could save around a hundred bytes on the larger ones just by omitting the closing parentheses/quote.

[EvanED]

Code: Select all

"chosen by fair dice roll.
"guaranteed to be random.
Disp(4

Disp( Reminds me of my Ti-83, but I don't know if there were comments. So probably not.

Putting a String on its own line with nothing else counts as a comment. Either that, or it prints the string... I don't remember

The TI-85 doesn't interpret strings on their own, so you're almost certainly right.

[Dustbin]

Let's take this a step further... to an A86 function:

Code: Select all

RandN:
  SUB AX,AX
  MOV AX,4
  RET

To be fair, there's no simple way to return the value in A86... could have pushed it to the stack... but that's not a lot of use, as we have to pop the IP (Instruction Pointer) back off the stack to continue program execution after the function... so that's largely redundant as we'd have to pop off the return value first...

If in doubt, use AX

Seeing that brings back memories.
SUB register, register is the fastest way to zero in x86 which is kinda weird.
Also why did you zero the register before moving 4 into it, I don't remember that being one of the x86 "trickses".

Simply because if you'd used AX outside of the function, regardless of whether this is a near or far execution, AX would still have a value in it. As 4 will be represented as a value just in AH (due to byte swapping), you could end up with a residual value in AL.... zeroing AX beforehand ensures you don't end up with any stupid results from left-over register data.

doh knew there was a reason I couldn't remember

[warriorness]

Code: Select all

"chosen by fair dice roll.
"guaranteed to be random.
Disp(4

Disp( Reminds me of my Ti-83, but I don't know if there were comments. So probably not.

Putting a String on its own line with nothing else counts as a comment. Either that, or it prints the string... I don't remember

The TI-85 doesn't interpret strings on their own, so you're almost certainly right.

But I use an 84 :\

[phlip]

Code: Select all

Function GetRandomNumber() as Integer
   Return 4
End Function


I haven't done VB in a while, but I think that's right

Code: Select all

Function GetRandomNumber() as Integer
   GetRandomNumber = 4
End Function

It has been a while for me also, but some things stick in the mind.

A couple more:

Code: Select all

[SP][SP][SP][TB][SP][SP][LF][TB][LF][SP][TB][LF][LF][LF]

Code: Select all

to rand
  output 4 ; chosen by fair dice roll.
           ; guaranteed to be random.
end

I'm sure I know some more stupidly-pointless languages, but I can't think of any right now...

[bugmenot]

If someone wrote that in C or C++, I'd shoot them. Not for the randomness, but because they forgot the void in the function argument list! Original K&R C doesn't support // style comments, so they can't use that as an excuse.

This is valid, correct Java code, even if it lacks a public/private declaration. Since Java is the current favourite of my university for teaching any real programming to newbs, I find this level of Java code quite often.

Based on my previously mentioned biases, I conclude it is Java.

[SiR]

Reverse Polish:

Code: Select all

4

I didn't forget Poland!

[pyg]

on the TI-83

Code: Select all

:"Random Number Generator
:"Guaranteed to be random
:While 1
:randInt(1,6)
:Disp 4
:Pause
:End

[EvanED]

If someone wrote that in C or C++, I'd shoot them. Not for the randomness, but because they forgot the void in the function argument list! Original K&R C doesn't support // style comments, so they can't use that as an excuse.

In C++ you don't have to and few do put void in the argument list. 'void foo();' is the same as 'void foo(void);', and the extra void just clutters things up.

For C you have a valid point.

This is valid, correct Java code, even if it lacks a public/private declaration. Since Java is the current favourite of my university for teaching any real programming to newbs, I find this level of Java code quite often.

Based on my previously mentioned biases, I conclude it is Java.

OTOH, claiming it is C or C++ has the benefit that it will compile on it's own, and you don't need to add any code around it.

7. ~: cat > delete.java
int getRandomNumber() {
return 4;
}
8. ~: javac delete.java
delete.java:1: 'class' or 'interface' expected
int getRandomNumber() {
^
1 error


But
9. ~: cp delete.java delete.cc
10. ~: g++ -W -Wall -c delete.cc
11. ~:

[EvanED]

BTW, arguing over what the language the code is is really stupid. The code is C++, the code is C, the code is Java (if you allow that to be an excerpt instead of an entire file), etc.

[imyourfoot]

Code: Select all

"chosen by fair dice roll.
"guaranteed to be random.
Disp(4

Disp( Reminds me of my Ti-83, but I don't know if there were comments. So probably not.

Putting a String on its own line with nothing else counts as a comment. Either that, or it prints the string... I don't remember

The TI-85 doesn't interpret strings on their own, so you're almost certainly right.

But I use an 84 :\

I've never used an 84, but it's my understanding that aside from a few extra functions/features on the 84 it's the same as an 83. On an 83 isolated strings don't do anything, so they basically function as comments (Note that the string still has to be interpreted, so it'll slow your program down if that's a concern). The exception to that is if the string is the last non-empty line executed by the program, in which case it will display the string in lieu of "Done". The same trick also works with numbers/variables/expressions, which can save a couple bytes if you need your program to output a result at the end.

[ringobob]

This comic is, most specifically, poking fun at programmers who believe that a "Random number" is an unpredictable number uniformly distributed between 0 and 1. Those are three criteria; and Mr. Munroe's function is a perfectly valid random number which breaks all three of those criteria at once.

It's not that programmers believe that a random number is "an unpredictable number uniformly distributed between 0 and 1", but rather that they want a number that meets those criteria, and the quickest lingual shortcut is to call it random, even though it might not be entirely correct. Though, to be fair, many probably do wind up equating the word with those criteria.

All that said, this comic gave me a chuckle when I realized that I was doing that myself when I saw the word random.

[shobadobs]

The code to print out '4' is:

Code: Select all

++++++++++++++++++++++++++++++++++++++++++++++++++++.

Oh, but

Code: Select all

+++++++[>+++++++<-]>+++.

prints out a more scrumptuous version of '4'!

[Pathway]

Discuss random number generators that, perhaps, are less random than one might expect, to great comedic effect.

I think the entire point is that the number was random--the randomness just occurred at an unusual time.

[Toeofdoom]

random numbers + a certain tv series = 47

1xintersphere timtam if you name the series.

[buge]

In whitespace:
http://pbunge.crimson.ch/tmp/random.ws

or with trailing newline:
http://pbunge.crimson.ch/tmp/random2.ws

[quaverknave]

I didn't forget Poland!

and that's how I know I read too many webcomics

Code: Select all

to getrandomnumber
 crt 43
 ask turtles [pd fd 14 pu fd 23]
 ca
 print 4
end

someone already got scheme. mah. there goes my humor and/or credibility.

yay for java based languages

[Arturion]

Code: Select all

/random { 4 } def

Anyone know this? Hint: Technically it's a scripting language, not a programming language.

[william]

random numbers + a certain tv series = 47

1xintersphere timtam if you name the series.

Star Trek?

[muteKi]

Code: Select all

"chosen by fair dice roll.
"guaranteed to be random.
Disp(4

Disp( Reminds me of my Ti-83, but I don't know if there were comments. So probably not.

Putting a String on its own line with nothing else counts as a comment. Either that, or it prints the string... I don't remember

The TI-85 doesn't interpret strings on their own, so you're almost certainly right.

But I use an 84 :\

I've never used an 84, but it's my understanding that aside from a few extra functions/features on the 84 it's the same as an 83. On an 83 isolated strings don't do anything, so they basically function as comments (Note that the string still has to be interpreted, so it'll slow your program down if that's a concern). The exception to that is if the string is the last non-empty line executed by the program, in which case it will display the string in lieu of "Done". The same trick also works with numbers/variables/expressions, which can save a couple bytes if you need your program to output a result at the end.

To all intents and purposes:

TI-83 = TI-84 = Silver Editions = Plus, etc. etc. = Sega Master System
It's a Zilog Z80 as the main chip in each of these, so they all use the same programming. Basically they just ported the BASIC compiler from one platform to the next because the ASM is the same.

TI-89 = TI-92 = Titanium Edition = Voyage 200 = Sega Genesis
This is a Motorola 68000 chip.

The only difference between the calculator models in each group is the amount of memory or the processor's speed (because the 83 and 84, etc. have processors with different clock speeds, though they're all z80).

If you wanted to make your own Genesis, you could start with a TI-89 model, but you'd probably need a bunch of other chips and a few other input sources, power supply, etc. (*Considers modding his calculator to eventually become the equivalent of a Nomad or 32X or something*)

[EvanED]

To all intents and purposes:

TI-83 = TI-84 = Silver Editions = Plus, etc. etc. = Sega Master System
It's a Zilog Z80 as the main chip in each of these, so they all use the same programming. Basically they just ported the BASIC compiler from one platform to the next because the ASM is the same.

TI-89 = TI-92 = Titanium Edition = Voyage 200 = Sega Genesis
This is a Motorola 68000 chip.

The only difference between the calculator models in each group is the amount of memory or the processor's speed (because the 83 and 84, etc. have processors with different clock speeds, though they're all z80).

If you wanted to make your own Genesis, you could start with a TI-89 model, but you'd probably need a bunch of other chips and a few other input sources, power supply, etc. (*Considers modding his calculator to eventually become the equivalent of a Nomad or 32X or something*)

Same with the 85 and 86, though these sport a somewhat redesigned interface, and somewhat different maths stuff. And the 86 has a rather better screen, and like 4 times as much memory.

(I was sore for years that when my parents offered to get me any calculator for up to $100 when I was in 8th grade, I chose the $99.99 TI-85 instead of putting 20 bucks of my own in for the 86. :-p)

[Toeofdoom]

random numbers + a certain tv series = 47

1xintersphere timtam if you name the series.

Star Trek?

+1 interspehere timtam for you. I can get a pic if you want... not very useful though :p

[buge]

Code: Select all

/random { 4 } def

Anyone know this? Hint: Technically it's a scripting language, not a programming language.

postscript?

[Arturion]

Code: Select all

/random { 4 } def

Anyone know this? Hint: Technically it's a scripting language, not a programming language.

postscript?

Got it! (You get a cookie!)

On my internship with a university computing science professor last summer, I ended up learning postscript and writing a graphing "program" in the last two days. It actually turned out quite well, he was happy with it.

[kakos]

If someone wrote that in C or C++, I'd shoot them. Not for the randomness, but because they forgot the void in the function argument list! Original K&R C doesn't support // style comments, so they can't use that as an excuse.

If someone wrote that in C or C++, I'd shoot them for writing it in C or C++.

PS: I'd also shoot them if they wrote it in Java. Java is, by far, the worst of those three. *spit*

[damaless]

Let 3 be an arbitrary natural number.

3 is prime.

Since our choice of 3 was arbitrary, all natural numbers are prime.

[william]

3 is prime, 5 is prime, 7 is prime, by induction, all odd numbers greater than two are prime.

Can't remember the rest though.

[kakos]

And the great logicians of yore cry out in precisely 350 GW of posthumous agony as you completely butcher logic.

[william]

Yeah, I know. I didn't make the joke though.

I remember the CS version of it is 3 is prime, 3 is prime, 3 is prime, 3 is prime...

[aldimond]

If someone wrote that in C or C++, I'd shoot them. Not for the randomness, but because they forgot the void in the function argument list! Original K&R C doesn't support // style comments, so they can't use that as an excuse.

If someone wrote that in C or C++, I'd shoot them for writing it in C or C++.

PS: I'd also shoot them if they wrote it in Java. Java is, by far, the worst of those three. *spit*

What language would you prefer? /C(\+\+)?/ seems pretty reasonable to me!

[kakos]

If someone wrote that in C or C++, I'd shoot them. Not for the randomness, but because they forgot the void in the function argument list! Original K&R C doesn't support // style comments, so they can't use that as an excuse.

If someone wrote that in C or C++, I'd shoot them for writing it in C or C++.

PS: I'd also shoot them if they wrote it in Java. Java is, by far, the worst of those three. *spit*

What language would you prefer? /C(\+\+)?/ seems pretty reasonable to me!

(defun lisp () (lisp))

That's my clever way of saying "Lisp forever!"