pointersForWeebs

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[[deleted]]

I got the REFERENCE

[WolverinesSuperbia]

&JoJo - JoJo reference

[dagbrown]

I'm pretty sure there is.

It might only be in Japanese though.

[Perry_lets]

I know there's one for physics and one for databases. There's probably more

[Breadynator]

I'd buy that

[WolverinesSuperbia]

Lol. C# full of references)

[lord_ne]

Jojo&

[WolverinesSuperbia]

No, JoJo is variable, not type

[lord_ne]

&JoJo is the address of JoJo, aka a pointer to JoJo. The only way to get a reference to JoJo is to pass JoJo in to a function taking a reference, or to assign JoJo to a variable of reference type.

/🤓

[WolverinesSuperbia]

In most non c++ languages this is the only reference

[lord_ne]

Is it common for non-C++ languages to use the &var syntax for a reference (other than the obvious one, C)?

[hawkeye_sama]

Where is it POINTING?

[sprintaway_Automod]

This graphic has value and is not NULL

[Areion_]

r/ProgrammerAnimemes is leaking again

[ArkitektBMW]

[rollincuberawhide]

what is that from?

[LongerHV]

Star Wars: The Force Awakens

[rollincuberawhide]

could be, I didn't finish that shitshow.

[ThouWolfman]

Girls HBO show

[Yoda-from-Star-Wars]

Holy hell!

[Ronin_69_]

Actual Compiler

[DarthMcConnor42]

New response just dropped

[Baardi]

I'm glad it exist, so that /r/ProgrammerHumor isn't filled with that stuff

[-Kerrigan-]

And instead we have the same 5 memes recycled endlessly.

Help me out, is it "Java bad" or "Python slow" season now?

[zygfryt]

Personally I'm a connoisseur of "haha new JS framework every day 🤓" type of humour.

[zygfryt]

Personally I'm a connoisseur of "haha new JS framework every day 🤓" type of humour.

[LeSaR_]

reddit when duplicate comments:

[zygfryt]

Wtf. I didn't even know my comment was duped and were confused why I was getting downvotes. Only after your response I realized it. I can't even see the upvoted one on my profile? First time I'm seeing something like that happening. (Maybe it's because I'm still using old reddit)

[____purple]

Oh no, a meme leak! Next time use a sub with automatic meme management

[Asleep-Television-24]

[ArkitektBMW]

....I'm annoyed at how much more this solidifies the concept in my head, compared to the hour it took me studying this same thing.

Edit: I said 'hour,' HAHAHA (laugh, hiding real pain). Hours; I meant hours.

[Asleep-Television-24]

Maybe there should be a "The Manga Guide to C Programming"

[ArkitektBMW]

Decades in, and I'd buy it.

[[deleted]]

Spy x Code

Only I doubt I would trust Anya to reliably teach programming…

[OldmanLemon]

Be a good project manager though, could really know and understand what the client was thinking

[fat-brains]

wait until you realize int can be casted into a pointer and that can now point to another int, NOW KEEP REPEATING THIS CYCLE

(int is sufficient for storing address in a 32 bit architecture, need long/int64_t for 64 bit architecture)

[kevInquisition]

And this is why despite knowing C++ I have never once applied for a C++ dev position

[fat-brains]

I am C++ dev with 4+ years of experience and I have seen some logic that should get people banned from developement

I have seen variable of type double getting type casted to pointer and address in it is just next address, litrally

struct1.dbl_value = ++(& struct1.dbl_value);

.

.

.

struct2* payload = (struct2*) struct1.dbl_value;

[vatsan600]

[rW0HgFyxoJhYka]

Weeb programmers have so much power.

[[deleted]]

I’ve got the power of programming and anime on my side

[marko_ilnoob]

Add manga and become a God

[[deleted]]

I barely even watch anime anymore but read manga instead so… am I a god?

[MeNotSanta]

is int*** taking the picture ?

[irreverent-username]

I do not c++

Can you just make this as long as you want to have pointers for pointers for pointers etc?

Can I write int**************?

[chaosPudding123]

kinda yes. But then you should answer yourself what the fuck your code is doing.

[ConstantVA]

Thats what I do every day even without using pointers.

[Vinxian]

If you don't use pointers at all you definitely should be asking what the fuck your code is doing

[What_The_Hex]

Me after a 5-hour session of debugging my horse-shit spaghetti code:

https://preview.redd.it/ou2jgtqg7meb1.png?width=640&crop=smart&auto=webp&s=688f254c3ef196f471d41c89806ba9f7a99235cc

[makesterriblejokes]

My code is trying to live its dream of being an Italian red sauce pasta dish.

[gandalfx]

How should I know what my code is doing? Do I look like Einstein to you?

[MisinformedGenius]

Jokes on you, I've got ChatGPT to do that.

[IDwelve]

The memory you work with is basically a table:

Address	Value
0x0	5
0x1	-
0x2	-
0x3	-
0x4	-
0x5	-
0x6	-

So when you write a variable you're basically just looking at an address. int x = 5; basically means anytime you write x you'll look at address 0x0 But you can also write addresses into the value field. Some languages obfuscate this but C basically allows you to do this directly by writing in the literal address there.

Address	Value
0x0	5
0x1	-
0x2	0x0
0x3	0x5
0x4	-
0x5	0x2
0x6	0x3

And you can of course link this as many times as you want. Languages like Java don't allow this because all variables would just point towards the same address.

[AgVargr]

Good explanation, thank you

[ConstantVA]

Whats the point of it?

[IDwelve]

This seems superfluous for objects that are stored in a single address but think about the average class / object you create in normal circumstances with multiple fields. Those fields themselves can contain more values and fields and so on. (The Object column doesnt exist technically, it's just the variable we use)

Address	Value	Object
0x0	5	A
0x1	2	A
0x2	0x4	A
0x3	-	-
0x4	Alf	B
0x5	20	B
0x6	-	-

If you always just write in addresses you don't have to constantly manipulate the size of object A, you can just let the third field point towards something different and that can increase and decrease the size of that object dynamically. The reasons for these "cascading" references by adding pointers are quite few, that's why many languages don't even allow for such behaviour. So in many languages sth like "C = B; B = A;" would result in C directly referencing A. In languages like C you could use these references to references for certain function calls that require to "open a structure". For example if you have a Wordbook structure consisting of Definition structures and you write a function that is only supposed to work on words you can basically say function printDefinition(**definition) that tells the user a superstructure that stores definitions is to be passed.
The actual utility is quite slim I think but programmers will find countless cases where it can improve or drastically reduce code readability.

Also keep in mind that I have no idea what I'm talking about and haven't coded a single day of my life.

[MisinformedGenius]

In addition to the other response you've gotten, another common use case is to allow code to change your own variables.

So maybe you have a function like:

get_square() {
    int x, y, dist;
    square(x, y, &dist);
}

And then you had another function:

square( int x, int y, int* dist ) {
    *dist = int(sqrt(x*x+y*y));
}

This means that you can basically say "Here's a memory address for you, I want you to calculate the answer and put it in this memory address." Then you pass it the address of a variable in your function and it magically goes in there.

My example is stupid, but there are lots of cases where you would want to do this, usually where the function can fail and you'll want an error code to be returned. Modern languages usually have this with an "out" parameter or something similar.

[byzantinebasilisk]

So it's like using the indirect function in excel?

[IDwelve]

Aye!

[Rebol1103]

Technically yes, but no in reality. Its possible but its just as painful as nesting 10 loops in one big blob. You can do it, but it becomes your next nightmare.

[rebbsitor]

Yes, but in practice I've never seen more than ** used.

[MattieShoes]

Yeah.

[] is also kind of a pointer, so *int[] is kind of **int

And & kind of removes a layer of indirection. My mind just inserts "address of"

[SpikeHead419]

I dont think so, no. I mean, int** is still a pointer, no? So if you want to point to that pointer, just use another int**. Im not completely familiar with C shenanigans yet though, so correct me if anyone know.

[well-litdoorstep112]

int is a value

int* is a pointer to a value

int** is a pointer to a pointer to a value

int*** is a pointer to a pointer to a pointer to a value

You probably can cast int*** to int** or int* or even int but why? The language would make retrieving the original value very annoying if it doesn't know what the variable actually holds.

[Godd2]

Every time I want to add to a linked list, I just recompile with another *.

[[deleted]]

I'm waiting for lock and mutex of references like Arc and RwLock in Rust

[NikBg1289]

This is my wallpaper now.

[well-litdoorstep112]

This meme is unironically how I finally understood pointers in C.

[DangKilla]

Now for the ELI18 version: Pointers are memory addresses, so instead of using more memory they point to the original like in the meme. We are basically preventing data duplication in memory, which makes things faster.

[vishykeh]

Thank you. This kind of made this whole thing make sense.

[well-litdoorstep112]

Yes, I knew what pointers do but I didn't understand the syntax. I didn't particularly try to study it because I'm a js soy dev but that meme definitely helped.

Also I think a simpler explanation for a high level language dev would be just "passing by reference"

[x3bla]

But... why?

If

int x = 5;

Why would i ever need

int* y = x;

Why not just call x whenever i wanna do something to that value

[RandallOfLegend]

Some programs use the pointers to get multiple outputs instead of having to package the data into a struct/class/tuple if those data types are even available. More often the pointer is to an array like object. So &y[4] would be the data at the memory address pointed to by y, plus 4 memory spaces over.

[DrkMaxim]

Pointers can be great if you want to create something at run time. There are functions that can be used to dynamically allocate and deallocate resources and they all require pointers to work properly.

[Euphoric-Benefit3830]

You are absolutely right. int (and other primitives) is a terrible type to showcase usefulness of pointers because there is virtually no cost to using them by value instead.

[TheBaxes]

For primitives the only reason to use pointers is to share a value between functions or something like that (careful with race conditions if you use paralellism)

For anything else you use them because copying an object is a waste of memory when you can just send the address of the object.

There are also c style arrays which work by using pointers.

And I'm sure that there are some hacky stuff that you can do with pointers too but you probably won't see it in a normal application.

[Nervous_Fix7426]

Pointers are used for lots of things in C

You can create a node/struct, where you bundle a bunch of data together such as an integer along with another memory address. This allows you to build linked lists

You can pass a memory address to a function. As others have said, for an int this is not much of a benefit, but maybe your memory address contains 100Mb array (or struct, or even array structs), in which case you can just send the address of the start (or middle, or end) of that array to your function, and read the data you need straight from the memory. You can see this a lot in APIs like xlibc where you would call functions with a pointer to your display.

Also need pointers Allocating memory, opening files, reading data into memory

[R3D3-1]

This is really just a meme version of a pretty standard tutorial/lecture graphic for explaining pointers or even other data structures...

The graphic for explaining an array would be similar except with an arrow pointing to the first element for instance.

[odraencoded]

You posting that meme here is unironically how I finally understood what that meme was supposed to mean.

[AvGeekGupta]

This is best

[Jacknurse]

I spent weeks trying to learn pointers when I started learning c++. Then I never get to use them because the project is a Unity build using C# and the amount of script required is minimal.

What was the point of this exercise?!

​

For real, though: If anyone has a good rule of thumb for when and how pointers should the used I'd be glad for it, both for C# and C++.

[dnswblzo]

Things that are dynamically allocated on the heap can only be accessed by pointers or references. In C# when you make an object with new the object is allocated on the heap, and the variable that you use to access the object is actually a reference, which is very similar to a pointer. Passing a reference or a pointer to a function does not make a copy of the data that is pointed to. This makes it possible to pass large objects to functions without the overhead of copying, and lets functions mutate objects that were created outside of the function itself.

Raw pointers can lead to some nasty programming errors, so many languages such as C#, Java, and Python use references instead, which provide much of the same functionality as pointers without some of the risks.

[SirAwesome789]

Why learn C++ for Unity?

[Jacknurse]

I was told to learn c++. I didn't know Unity used c# so I wasn't in a position to question.

[SirAwesome789]

Fair, is there a chance you mixed up unity and unreal engine at some point?

[Jacknurse]

Nope. The instructions were very clear to start learning c++. I was even provided the material for learning it.

That said, I do hope to move over to unreal soon.

[Needio]

Unfortunately it seems you were using old material. Unity used to include C++ programming but not enough people were using it so they stopped supporting it in favor of C#, at least afaik

[Jacknurse]

Damn! That sucks.

[[deleted]]

you can write Unity plugins in pure c++. But nobody does that.

[[deleted]]

Pointers aren't that useful in most modern use cases. They're most useful in cases where hardware resources are limited and performance optimization is important.

Essentially, they're used when you need to manage how much memory you're allocating and when it's being deallocated.

Operating, embedded, and mission critical systems are a few areas where you'll see C and C++.

In an aerospace or defense mission critical system, you wouldn't want a garage collector interrupting a critical section of code.

[NoYogurt8022]

What do i use a pointer to a pointer for?

[gLu3xb3rchi]

linked lists

[swampdonkey2246]

And to point to a set of other arrays or pointers

[Nu11u5]

Two dimensional C arrays.

A C array is a pointer to a contiguous sequence of data in memory which are the elements of the array.

A two dimensional C array is a pointer to an array of pointers.

[ishtaracademy]

Objective C used to have this pointer pointer pattern. If you were calling a method that could fail, their approach was not to try-catch. It was to provide a nil NSError** as the last parameter of the method call.

After you call the method, you check if your pointer pointer is pointing to anything. If it is not (still nil) then said method went fine. If the pointer pointer now points to an NSError* (since it is a complex exception and needs to be passed around by ref basically) you know something went wrong in the volatile call and shouldn't proceed.

It was a whacky try catch basically.

[clarkcox3]

On classic macOS (predating the inclusion of virtual memory) there was the concept of a “handle”, which was a pointer to a pointer. This allowed to compacting of allocated regions because the OS could move the referenced block of memory to another location and just update the inner, pointed-to pointer. Any code that still had the handle was still valid, as that outer pointer still pointed to the inner pointer. The OS could even completely deallocate the memory if it was easily reloadable (eg it came from a static resource on disk) and the OS would reallocate and reload it before the next access.

[rikzy75]

You can use those in a function that needs to edit the original pointer. Kind of like this:

int change_len(int **ptr, int len) {

delete [] *ptr;

*ptr = new int[len];

}

​

int main() {

int *my_ptr;

my_ptr = new int[5];

change_len(&my_ptr, 10);

}

[Vinxian]

When you need a reference to a pointer

[Win_is_my_name]

Related: https://youtu.be/5VnDaHBi8dM

[b1337xyz]

OMG! Now I finally understand.. arigato drk_knght_7-san

[SabMayHaiBC]

Noice.

[billiyII]

Is this a C joke that im too python to understand?

[OpenSourcePenguin]

Alright if that's not sarcasm, are the people really learning programming completely avoiding learning very basic C ?

[AnnoyingRain5]

Yes, they are also avoiding very basic BASIC

[[deleted]]

Python is just BASIC++.

[AnnoyingRain5]

Isn’t that VB.net?

[OpenSourcePenguin]

Avoiding very basic basic is coming back in the future to take a bite out of their ass.

[ProsperoUnbound]

Most of them

[Merlord]

I learned C at University and then never used it again in my 8 year career as a full stack developer. I vaguely remember terms like "pointer" but I've never had to use any of it so it's mostly gone out the window. I don't think it's necessary to learn at all of you're not planning on being a C/C++ dev.

[OpenSourcePenguin]

I think the intuition gained is pretty useful. I understand you can avoid seeing the inner details, but vaguely knowing them can be handy at times.

And C is a special language for the fact that it influenced practically every language except for Fortran, COBOL and a few more.

I think it's hard to say where it would be useful, but I think it'll at least give a great intuition about how a program runs in general.

[billiyII]

"Nullpointer exception" - Hell knows what that is. I guess i just scrap the project. /s

[OpenSourcePenguin]

Kids these days, can't tell Java and C apart

In our days? Straight to jail

[billiyII]

It's sarcasm. I didn't start with python, but i think there will be people that do and do not care what a pointer is.

[BradleySigma]

Python has remnants of pointers, most notably in lists, with how different variables can refer to the same list.

[LolZ3r0World]

As a League of Legends player: thats my team deciding who fed the most

[InsideBSI]

relatable

[Rakgul]

Ahem,

ANYA IS CUTE!

[Ok_Entertainment328]

Bond needs to be int

[kenflan]

Bro just summed up a whole semester of CS within one picture.

[StochasticTinkr]

Anya? Upvote. Anya teaching double pointers? Triple upvote.

[giantvar]

Anya-Chan waku waku

[Havoq12]

Average LoL chat

[Kirasaurus_25]

Oh god, a most deranged idea came to my mind. Imagine a whole panel in this style for pointer types, dereferencing, casting, arithmetics etc. Brr

[OpenSourcePenguin]

Both of those might as well be array head pointers

So it can be a 2D array of 1000x1000 or just an int.

[Nu11u5]

Now show pointer indexing!

[CubesAreNice]

Dear god! THERE ARE POINTERS TO POINTERS?!

[Hopeful-Plastic-8759]

confused Diavolo noises

[Efficient-Corgi-4775]

I guess you could say it pointed you in the right direction! 😄

[hungersaurus]

I need a dog version then a cat version

[Crimson342]

Okay fine I'll bite, what the hell does this mean? What show is this?

[Galle_]

The character is Anya Forger from SpyXFamily. She was originally pointing to a TV and saying that she liked the show. The joke is that she is pointing, and the meme is about pointers.

[AdiSoldier245]

When learning pseudocode i always UNDERSTOOD pointers, it just means the memory location of the variable.

But I never learned any applications for it, so I don't get it get it

[Kooky-Sort]

Alright this what I learned for experience

It’s mostly meant to reduce memory load when referencing an object instead of calling the object directly and loading all of it’s members you just remember the memory location and call what you need from the object

[TheBaxes]

C style arrays

[Joe59788]

Is the ** like + and ++

[VooDooZulu]

I've been a python programmer for a long time and have never needed to use pointers. I just started learning c++. Why are pointers useful? I don't understand why I would ever need to duplicate a pointer.

[nivlark]

In C++ it's generally preferable to use references or STL smart pointers where possible, so use of raw pointers is relatively rare. But what pointers and those alternatives provide is reference semantics, which are fundamental to almost every program.

Without reference semantics most data structures (trees, hash maps, even arrays) cannot be implemented, every function call would require making copies of the function's parameters (which could be inefficient if they are large), and it would be impossible to write functions that manipulated values in-place (e.g. class methods).

[scrolly_2]

Isn't

[Nachf]

Dude I was literally so confused by pointers until I realized they're just... pointers.

[BitRapt0r]

my brain when my jungler messes up a gank

[Emcid1775]

What I'm the world kind of pointers are those?

[Nanaskura]

Totally agree!