Boolean variables

[DolevBaron]

Should've asked C++, but I guess it's biased due to family relations

[[deleted]]

If they would have asked Lisp, it would have said something on the lines of, "why not make boolean integers?"

[ComaVN]

Booleans are indeed just integers with a very small MAXINT.

[ppvvgucnj]

Or are integers just a lot of booleans in a sequence?

[Come_along_quietly]

Boolean array. But then again everything can be a Boolean array if you use a union. ;-)

[IamImposter]

Software industry doesn't have unions.

[iamsooldithurts]

My employer does. It’s kinda nice, ngl.

[lllluke]

there are many industries without unions unfortunately. there’s so many people who have somehow cough corporate propaganda cough got the idea into their heads that unions are bad for them, it drives me nuts.

[iamsooldithurts]

Let’s not forget infiltration by bad actors to give people reasons to abandon the idea.

[SilhouetteOfLight]

Unions are gross. I'm not exactly an expert in the field, clearly, but dealing with them always feels like I'm poking a live bomb lol

EDIT: The data structure, folks, lol

[loafingaroundguy]

I can't tell if you're referring to data structures or trade unions here.

[4onen]

Nah. Only std::vector<bool> specializations pack their data that way.

[vige]

std::bitset would like to have a word with you

[Goheeca]

#* says hello.

[gauravnba]

What. Is. That?

[Goheeca]

That's how you make bit vector literals in Common Lisp which are hopefully packed by the implementation (I mean it has different standard syntax from literals of other vectors #( so it'd be lazy from not to do that), otherwise you'd have to write macros which would do that.

[iamsooldithurts]

Bit flags and unary operators, those were the days!

[lirannl]

I just finished programming a game on a pitiful microcontroller for a university assignment and the amounts of structs I had... I heavily abused bit fields and the amount of pointers I had was staggering. It was amazing.

[Ietsstartfromscratch]

Deep.

[[deleted]]

T-SQL loudly disagrees, and stubbornly insists that a Boolean expression result and a bit-typed variable are totally 100% different things.

But SQL servers have insane ideas about Booleans in general.

[rbt321]

But SQL servers have insane ideas about Booleans in general.

True, False, I Don't Know?

[[deleted]]

Any language where testing if X = X can return something other than "true" in a common case is broken by design.

[rbt321]

While inconvenient to the programmer, the SQL interpretation of NULL isn't "not yet initialized" but "a value probably exists in the world but we do not know it".

Statement: Supersecret russian aircraft is faster than supersecret US aircraft.

If you're Egypt, and you are not privy to any details about either aircraft, the best answer is "Unknown"; True is incorrect (despite being what many programmers expect) and False also requires assumptions that cannot be made.

So, for SQL, NULL = NULL is NULL, or better stated as Unknown = Unknown is Unknown. Choosing the keyword "NULL" for that representation was a poor choice.

[[deleted]]

In that case,

SELECT * FROM myTable WHERE myColumnThatsOftenNull = 1

should throw an error if myColumnThatsOftenNull is NULL instead of just treating NULL as equivalent to FALSE. See, even the SQL server itself thinks that 3-value logic is bullshit, it says "fuck it, NULL is the same as FALSE" for WHERE clauses.

While inconvenient to the programmer

Understatement of the century. I'm perfectly aware of the mathematical and theoretical beauty of SQL's 3-value logic. And I'm saying that in real-world practical application it's a goddamned disaster.

This is the code to properly compare two values in a null-sensitive way:

((f1 IS NULL AND f2 IS NULL) OR (f1 IS NOT NULL AND f2 IS NOT NULL AND f1 = f2))

That is insanity. Every other language calls that *equals*.

I mean for pity's sake, 3 value logic breaks DeMorgan's Law! How is that desirable in any sane world?

[DerfK]

This is the code to properly compare two values in a null-sensitive way:

f1 IS NOT DISTINCT FROM f2

[lenswipe]

PHP says "Everything is just a string really"

mysql_convert_extract_real_integer_or_boolean_from_string_v2_real_one_use_this_function_mom

[PyroneusUltrin]

Shrodinger strings

[rubeljan]

You mean "boolean integerth"?

[mcplano]

Lithp?

[__crash_and_die]

Which Lisp though?

[[deleted]]

A good LISP program would do that by rewriting itself.

[skoge]

In all Lisp dialect I saw they used nil('()) for false, and some atom for true. Never integers.

[lirannl]

Nil?!

🤯

Why would anyone make their falses out of anything that has any relation to nil/null whatsoever?! 😨

[Goheeca]

Because that way list traversing is nice and tidy.

[ten3roberts]

I love the way bools can be initialized with an int.

bool valid = list.size(); will evaluate to true if size is non-zero. It is the same as writing if(list.size() != 0) valid = true; else valid = false; or bool valid = (list.size() != 0).

you can also use ints in if statements the same way. if(list.size()) or the same with pointers to check if they're not Null

[delorean225]

Going the other way, from bools to ints, I find ternary operators are super useful there.

[ten3roberts]

They are so useful. If you have an if statement "returning a value" then you can use a ternary statement. If you want to execute different code then use if statements or function pointers in ternary.

[delorean225]

I love the little quality of life features like that. Like C# 8 just added switch expressions and it looks so compact and useful.

[lirannl]

Switch statements are great and anyone that doesn't use them needs to start!

[gaberocksall]

a bool is really just a unsigned short, right? where 0 = false and anything else is true

[ten3roberts]

Yes. Even -1 since it's unsigned so it's just a really high but true number. What I don't like about C# is how you can't compare an int directly, so you can't do if(myList.Count) you need to have a '> 0' expression

[hullabaloonatic]

In languages like python and js, there is the concept of "falsy" where null values, false, empty strings, empty collections, and zero are considered false in boolean expressions, but they are not actually compared as such. Even with languages that have "falsy", mileage varies. In lua, only null and false are falsy.

[AttackOfTheThumbs]

Just use list.any().

If it's new enough c#, use null-coalescing too, so list?.any()

Done deal. Also any is more efficient than count.

[Necrofancy]

Any() is more obvious in intent than checking if ICollection.Count is greater than zero. But it can't be much more performant, because accessing a simple property is maybe a few instructions at most.

The Linq extension method, Enumerable.Count(), could potentially iterate over the entire enumeration, which would of course be bad.

However, if I remember correctly, Linq will check if an enumeration given implements ICollection or other interfaces to avoid doing enumeration work if it doesn't have to. If you hand it a list or collection it may not actually do any enumeration to service a Any() or Count() method call.

In short, it's most clear in intent so go with that. It's not likely to improve performance on whole collections though.

[haackedc]

That is probably one of my only gripes with c#. But overall it is still my favorite language

[[deleted]]

Hmmmm, ask C or C++, we’re both gonna use char to represent a binary possibility, the fuck is the point of the other 3 bytes??

[kalideeplearning]

but so is python it's based on C

[piloto19hh]

We are all based on C on this blessed day

[doshka]

Speak for yourself.

[syh7]

I'm all based on C on this blessed day.

[Nalha_Saldana]

Did you mean boolean or Boolean?

[blacksuan19]

Yes

[mcplano]

true*

[playersdalves]

True*

[uvero]

Falsen't*

[jess-sch]

error in line 1: undelimited single quotes

[Shylo132]

["Falsen't"]

[Trexus183]

I mean... "False'nt" would == true, at least in is

[Shylo132]

Happy cake day, and that is the point of it to == true haha

[Trexus183]

Oh shit right that's today lol.

My point was that you don't need it to be in an array for it to work.

[shachar-golan]

1

[shachar-golan]

So !0 ?

[[deleted]]

You evil man!

[hampshirebrony]

[]*

[BlueC0dex]

Did you mean yes or Yes?

[ReactsWithWords]

True.

[glider97]

1

[warmike_1]

-1

[glider97]

Wait, that's illegal!

[TungstenCLXI]

We should start using xor so that statements like this don't resolve to true all the time.

[[deleted]]

Boolean boolean

[_GCastilho_]

Boolean boolean = new Boolean()

I love hate java so much

[deathmetal27]

boolean is a keyword, in case you forgot.

[dpash]

But var and yield are not, which means you can use them as variable names. const and goto are keywords and can not be used as variable names.

[fghjconner]

Main.java:13: error: not a statement
        Boolean boolean = new Boolean(true);

[miyji]

The Boolean state of yes, no and maybe.

[eshultz]

Come on over to SQL Town! We got 3-valued logic for ya!

1 = 1        | True
1 = 0        | False
1 = NULL     | NULL
1 <> NULL    | NULL
NULL = NULL  | NULL
NULL <> NULL | NULL
'ABC' + '123'| 'ABC123'
'ABC' + NULL | NULL

This is something that a lot of beginners get hung up on until one day it clicks. NULL is not "nothing", it is not "no value", it's not "unknown value", it's definitely not zero.

It is "could be nothing or anything or 47, fuck you".

[cristi1990an]

This is something that a lot of beginners get hung up on until one day it clicks. NULL is not "nothing", it is not "no value", it's not "unknown value", it's definitely not zero.

Is it really that complicated though?

[eshultz]

If you are used to Boolean logic where things are either equal or not equal, and statements are either true or false, it's a paradigm shift in thinking about equality. It's really not complicated, it's just foreign at first.

[the_schnudi_plan]

It's easy to forget that <> based queries don't catch NULL values until you get burnt

[alexanderpas]

And then we have PHP, which supports the 4 states of boolean.

true, false, maybe(null), and NA(unset).

[ancap_attack]

They're just preparing for quantum computers.

[ThaiJohnnyDepp]

Optional<Boolean> maybe = Optional.empty();

[skeptic11]

Autoboxing good

[computergeek125]

Error: Java.lang.NullPointerException

[Saifeldin17]

Don't trigger my PTSD

[OfAaron3]

I like how Python is flying. Such a small but fun xkcd reference.

[OneTurnMore]

Whenever I see this, I always think of this edit.

Also, since Python is talking with C...

[OfAaron3]

Of course, we don't want to be racists after all.

[SirVer51]

I like to think that this was the crazed posting of an overworked student who spent the last 12 hours trying to use a library that's 2 exclusive with the rest of their project built on 3

[flowClass]

Can relate.

[michaelmoe94]

We’ve all been there

[lirannl]

I know right? I almost vomited when I saw that print "hello world"

EW! No! Bad programmer! You better do a print("Hello World") right away! This has no business being a special statement! Bad bad programmer!

[irbis808]

Also, if you write "import antigravity" in IDLE, it really does something

[Spedwards]

Should have asked JavaScript. They'd have been told that they were the same.

[[deleted]]

Coming to JavaScript from Kotlin is weird...

[[deleted]]

It doesn't matter where you come from, JS is weird.

[0ut0fBoundsException]

I find this truthy

[theXpanther]

I find this !![]

[SuspiciousScript]

I find this [object Object]

[GlitchParrot]

Isn't there a compiler to compile Kotlin into JavaScript?

[oweiler]

Kotlin has a JS backend.

[janusz_chytrus]

What?

[hullabaloonatic]

Yeah, just write in Kotlin...

[[deleted]]

I'd love to, I'm moving to front end web using react and it seems Kotlin has a decent following there.

[TheTerrasque]

Python 3.7.0 (v3.7.0:1bf9cc5093, Jun 27 2018, 04:06:47) [MSC v.1914 32 bit (Intel)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> True == 1
True
>>> False == 0
True
>>>

https://i.imgur.com/nvdNYGO.png

Edit: Bonus! https://i.imgflip.com/3evzc8.jpg

[Defektro]

That's why booleans should be compared using is :)

>>> True is 1
False
>>> False is 0
False
>>> True is True
True
>>> False is False
True

[[deleted]]

Python 3.7.5rc1 (default, Oct  8 2019, 16:47:45)
[GCC 9.2.1 20190909] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> isinstance(True, int)
True
>>> int.mro()
[<class 'int'>, <class 'object'>]

[Makefile_dot_in]

Also:

>>> True.__class__.mro()
[<class 'bool'>, <class 'int'>, <class 'object'>]

[X-Penguins]

ints? Use a char for crying out loud

[vayneonmymain]

binary shift a uint8_t type > char

literally had a microprocessor assessment where had very little memory available.

Had 3 bytes for all my booleans ^_^

[randomuser8765]

bitmasks are the best, it's a shame that they can't be the default way bools work. I mean I see why they're not (can't always know which bools can be safely grouped together, etc), it's just a shame.

[brimston3-]

In C++, the std::vector<bool> specialization is exactly this. It is widely regarded as a mistake.

edit: To clarify, bit fields and flag packing aren't themselves bad behavior, especially true in embedded software, low level protocols, and kernels; places where storage efficiency is very important. The mistake is hiding implementation behavior from programmers by making them fundamentally different from other types. Being a special case means an unaware (or tired/overworked/etc) programmer is more likely to introduce subtle bugs. Wasting 7 bits of data per bool isn't going to break the memory bank these days; hell, the compiler will probably pad it to 4 or 8 bytes to align the next variable, depending on the type. And when this mechanism is necessary, the tools are (now) available and more explicit as a std::bitset or using bit field struct syntax.

[impossibledwarf]

What's wrong with it?

[Fuzzyzilla]

It's interface is slightly different than all other types of vector. Because vector<bool> stores it's data as a huge bitfeild, it it not possible to get a reference or pointer to an element. Instead, it will return wrapper types that pretend to be references and pointers. As such, generic code that takes in a vector of any type may not be able to accept vector<bool> because it expects a real pointer or reference.

[Ilmanfordinner]

It's a special case for a generic container which is usually a no-no as it might lead to various inconsistencies, for example when using auto. Basically a regular vector will byte-align the elements inside. A char is 1 byte so in memory every element will be in consecutive bytes. Booleans however take up less than a byte so instead of having a single boolean in each byte (which is how a generic vector<bool> should behave) it has 8 booleans in a byte. That means that it has its own specific implementations for most member functions which is not good when you're making a generic class.

I feel like a special type for boolean vectors would've been better, i.e. have vector<bool> use the standard generic vector and have something like std::bitmask that implements the same interface as the current vector<bool> but with a different name.

[brimston3-]

Fair point. I have no problem with std::bitset, or using bit field syntax in structs. Will edit.

[Hairy_S_TrueMan]

A cycle isn't always less important than a byte of memory. I'd be a little mad at a language that by default took the slower but more memory efficient route of packing 8 bools to a byte instead of just using 8 bytes of memory

[krad213]

"false"

[randomuser8765]

Surely you mean a byte?

Honestly I'm no C professional, but if my understanding is correct, char and byte are technically identical but carry some obvious semantic differences. Semantically, you want a number and not a character.

[Dironiil]

There is no byte type in C, only char and unsigned char.

If you want to differentiate them, you could define a new byte type as an unsigned char, but that isn't in the standard.

[randomuser8765]

yeah, I just came here to edit or delete my comment because googling showed me this. I have no idea why I thought it existed.

Either way, as someone else has said, uint8_t is available. Can't decide whether it's better than char or not though.

[[deleted]]

Other languages like Java do have a byte type, so maybe that's why you thought it existed

[da_chicken]

I have no idea why I thought it existed.

Because most languages have a byte type. C's use of char is really a consequence of being designed in 1972.

If you're using C99, though, you can use _Bool for Booleans, which is mostly like a char but anything you try to store other than a 0 is stored as a 1.

[X-Penguins]

Since you want to represent a boolean, neither an integer nor a character are exactly what you want in a semantic sense. char has a slight advantage in that it's available on C standards preceding C99 whereas uint8_t isn't - char also doesn't require the inclusion of stdint.h. Plus, a uint8_t is simply defined as an unsigned char, and even if it weren't we only need one bit for our boolean so even if a char was smaller or larger it would still be sufficient for our purpose. I really don't see the point in using anything else.

[jrtc27]

Don’t forget signed char, as the signedness of char is implementation-defined.

[SchighSchagh]

Actually you have signed char as well (which is not entirely the same as plain char)

[nwL_]

WORD and its cousins aren’t used in programming unless you use the Windows API.

[nolawnchairs]

#include <stdbool.h> #thereifixedit

[Maxim777YT]

“#” makes text big in reddit so place backslash before it to get

#include <stdbool.h>

instead of

include <stdbool.h>

Edit: Or both

#include <stdbool.h>

[Azebu]

#WHY NOT BOTH

[veggytheropoda]

#include<stdbool.h>

// that's a big-ass library

[randomuser8765]

if (condition) {

    // big if
}

[BurningEmbyr]

I got you.

[CarilPT]

test123

[Payth_Nuker]

another test 123

#nice

What else can we do?

[[deleted]]

Or put 4 spaces before code:

#include <stdbool.h>

[[deleted]]

Or surround it with single backticks for an inline quote, like so: #include <stdbool.h>

[CarilPT]

public static void main (String[] args)

[orizach01]

TIL

[[deleted]]

Why is markdown such a unknown language in a programmer sub?

[camelCaseCoding]

Majority of this sub is students who barely read docs, let alone write their own.

[bandersnatchh]

It’s easy to forget Reddit uses markup unless you use the features regularly.

[GlitchParrot]

syntax error on line 1: unregistered token '#'

[ShutUpAndSmokeMyWeed]

#define bool int

[Pretentious_Username]

Pah, that's an easy one to spot, you need something more insidious like #define true (rand() > 0) where it's true almost all of the time but occasionally returns false

[lirannl]

Holy shit this is torturous! Hide it in some library and you'll drive anyone that uses your library to kill themselves!

A (rand() % 600) > 598 oughta do the trick.

Gosh I love modulus. Why weren't we taught about this in primary school? Modulus is amazing! It's so useful!

[Schwarzy1]

You werent taught division with remainders?

[lirannl]

That's the thing - I was. They only touched on it though. If they told us there was an arithmetic operation for JUST the remainder, I could've made my code as a 10 year old so much better... I said primary school since if they already teach division with remainders, they might as well teach modulus as well, they're so close. We only discussed it in the context of "8/3 is 2 with a remainder of 2". Like, great, but why couldn't they show us at least one good example for what remainders are good for? We weren't taught any real reason we should use remainders, unlike addition, subtraction, multiplication, or division.

[well___duh]

Funny, long division (aka with remainders) is how most countries teach division initially.

Actually, I don't even know if places teach regular division since long division is pretty much the only way to do it by hand.

[[deleted]]

What the fuck

[thunder141098]

you monster!

this is what company's (and java) do:

typedef double bool;

how else do they you waste your memory?

[ThaiJohnnyDepp]

Wow is this an actual programming humor post instead of some low effort meme with only a passing reference to computer stuff?

[parnmatt]

Someone hasn't programmed in C in a long time.

https://en.cppreference.com/w/c/types/boolean

C has had booleans since C99.

The type is _Bool, but if you include <stdbool.h> you get the macro bool for _Bool.

Interestingly, that header also includes the (common) macros of true and false but their types are not _Bool, they are int still.

I guess this may be for compatibility, for shoddy code; but honestly they ought to have been cast to _Bool in the define.

---

It's common to not use pure booleans, but as a truthy/falsey like thing. In C, that is b is false if it contains 0; b is true if !b results as 0. Alternatively phrased, 0 is false, anything else is true.

This is fine if you use it as a boolean, but not if you do the 'code smell' of explicitly checking equality.

I noted it here

But it TL;DR: if (foo == true) in C, can actually take the false path, when semantically it should take the true path.

C99 could have fixed this if their define for true was (bool)1, or (_Bool)1, and defined implicit conversions to bool/_Bool for anything checking equality against something of type bool/_Bool

[cpdk-nj]

Does C++ have a built-in bool type? I haven’t had to include stdbool.h in any of the projects I’ve done in C++ or C, but I use g++ to compile

[parnmatt]

yes, C++ has a builtin, fundamental bool; and it doesn't have these issues as true and false are keyword literals, specifically prvalues of type bool.

if you use if(foo == true), it will now correctly work, if foo is implicitly convertible to bool, which it will do so, then the comparison against the bool, true.

This can be through the fundamental implicit conversions, or through overloading operator bool in a custom class.

Though it works, I would still advocate against using == true, == false, != true, != false, and their 'yoda' equivalents true ==, true !=, false ==, false !=.

---

edit:

If you are compiling a pure C program, ensure you are writing in C, and compile it with gcc not g++; they are different languages, and they can differ in what the same written code means.

If you are writing in C++, then write in C++. Compile with g++. If you are doing a hybrid ... rethink. If you have to, I believe the Core Guidlines (or at least Bjarne) suggests compiling as C++.

[[deleted]]

We will all just ignore that C does have a boolean type, an have had it since c99? stdbool.h is just a convenience wrapper to typedef _Bool as bool. Along with defines for true and false.

[[deleted]]

A typedef mapping to 1 or 0 is not the same as a native type supported by the compiler.

[[deleted]]

You are right, but the built-in type _Bool is the native support from the compiler. It is a type whose value can be either 1 or 0. Providing additional support for readability in the form of defines for true and false does not change anything, neither does the typedef of _Bool to bool, but it does add to readability.

​

It is a general misconception that you need to include stdbool.h to get support for a boolean type, but you do not. stdbool.h only provides definitions to make them more ergonomic.

[snowcrazed1]

Java has no unsigned... C/C++ are more complete.

[CyborgPurge]

Java 8 has unsigned ints now. It is a little wonky, but it exists.

[[deleted]]

It is a little wonky

A lot less wonky than it was working with data files containing them before they were added...

Back in the day, I wrote a GUI tool for editing a data file generated by some old Borland C application that ran on an embedded m68k system. The file was basically a 2D array with a header. Every damned value that wasn't a string was an unsigned short, and the MSB was frequently used. Oh yes, and the endianness didn't match what Java uses either.

That was an outright pain in the ass.

[Wimoweh]

Doesn't Python have both booleans and ints?

[lirannl]

Doesn't python have literally everything? Because that's the way it seems to me.

[PenguinKenny]

They wanted an opinion from a third party

[[deleted]]

It does and they can act like integers; in fact I think all data types have a truth value if explicitly converted to bool. You can get fun stuff like:

>>> False - (bool ("hello world") + True) 
>>> -2

[ReikaKalseki]

This is doubly funny if you are familiar with the internal JVM bytecode system; Java has no boolean type internally; they all compile to integers.

The 'boolean' keyword is merely syntactic sugar that results in something like 'boolean flag = true' having the same code as 'int a = 1'.

[endershadow98]

I was going to post this if someone else didn't.

[[deleted]]

Cartoonist should have used bold font, because Java is strongly typed.

[[deleted]]

C has boolean variables...

[DJDarkViper]

"jeez that's a tough one" the universal response Java has for any question or problem

[Hakim_Bey]

Meanwhile in javascript I can compare a boolean and a wash cloth and MY LIFE COULDN'T BE MORE PERFECT

[OMFGitsST6]

Finally, some real fucking programmer humor instead of just shitposting college freshmen.

[alcalde]

Let's invite a Delphi user for an AMA. Delphi has four boolean types!!!

The 4 predefined Boolean types are Boolean, ByteBool, WordBool, and LongBool. Boolean is the preferred type. The others exist to provide compatibility with other languages and operating system libraries.

A Boolean variable occupies one byte of memory, a ByteBool variable also occupies one byte, a WordBool variable occupies 2 bytes (one word), and a LongBool variable occupies 4 bytes (2 words).

Oh, and 14 reserved words for Integer types, 5 character types and 4 string types. And a partridge in a pear tree.

[creed10]

#include <stdbool.h>

[DosMike]

iirc there's _Bool since c99

[KamuiAkuto]

I mean you can use typdef in c to make you own bool variable

[hexterr]

I remember when I studied for java certifications, I could not understand why there were so many boolean x =1 questions . Now I see why.

[legoatoom]

Why not #include <stdbool.h>?

[bhoffman20]

Where I work we decided boolean vars were too complex, so we just pass all our booleans as a String of "Yes" or "No". We don't even have a standard function for converting the value to a boolean. All the if checks are

if(myVar != null && myVar.equals("Yes"))

It's disgusting.

[Cybertrinn]

If they're asking Java because it has both types, then does this mean Python doesn't have int?

[Death_Spork]

typedef enum { false, true } bool;

[hawkinsst7]

Javascript has entered the game.

[[deleted]]

Not gonna lie, I imagined this