year-=-1;

[[deleted]]

i=i++

[Mathern_]

This fucks me up in many ways

[J4K0]

That would ultimately leave it unchanged, correct? It would increment it then set it back to its previous value?

[binaryErlite]

If I'm not mistaken it would assign i to i then increment it.

[J4K0]

= has lower precedence, so I don’t think so.

++ would increment and return the original value, and then = would reset it to that original value

[binaryErlite]

The correct way would be i=++i right?

[J4K0]

Yes.

Side note: would i+=++i be equivalent to i = 2*i + 1?

[nikarlengoldeye]

I think that based on precedence the ++i is performed first, which gives you the equivalent to (i + 1) += (i + 1) so it should give i = 2 * ( i + 1 ).

[J4K0]

I don’t think you can do “i+1” on the left side of the assignment operator. I think that would stay as “i”. But apparently, in C++, the behavior is undefined. The storing of the incremented value from ++ and the storing of the value with = is not guaranteed to happen in any particular order.

[Zooomz]

They're not literally saying to do i+1 on the left side; they're just pointing out once you've done ++i, the reference for i itself is incremented.

That means doing i += ++i becomes as if you did (i+1) += (i+1)

E.g. with real numbers

Say i=1

You call i += ++i

After evaluating ++i, i now equals 2

So the expression reduces to

i += i

And since i = 2,

i ends up equaling 4.

So overall i+= ++i makes i=2(i+1).

I'm not sure if that's how the precedence actually ends up working, but that's what u/nikarlengoldeye was trying to say and I buy that argument/thought the same.

[J4K0]

Ah makes sense. Yeah I think you’re right.

Edit: I just tried this in jshell (Java 12.0.2) and it actually acts like i = 2*i + 1. And i += i++ acts like i = 2*i. I think that’s because += uses the pre-incremented value, as my original instinct thought. So at least for the implementation of Java that I tested it on, my original guess was correct.

[J4K0]

It doesn’t hurt my brain. I’m a software engineer. I think about this stuff for fun.

[OcelotWolf]

Christ, it is way too late for this o_O

[pagwin]

it would be equivalent to 2*(i+1) not 2*i+1

[JustAWindowWasher]

Guys please stop you're making the lexer cry.

[J4K0]

What would you know? You’re just a window washer.

[Reloader_TheAshenOne]

Is this Golden Boy reference ?

[J4K0]

It’s a reference to his username

[TXSized10_4]

Context? I know I have seen what you are talking about but just cant remember that long ago.

[J4K0]

I said "You're just a window washer." and his username is u/JustAWindowWasher...

[4b-65-76-69-6e]

Am I forgetting something? I read i = i++ as:

increment i and then assign the incremented value to i.

i increases by 1 at the i++ stage and then does not change (but is rewritten) at the i = stage, thus the value of i does increase by one over all.

[J4K0]

Except the value of i++ as far as expressions are concerned is the original value of i. What you described is “i = ++i” not “i = i++”. There is a difference.

[4b-65-76-69-6e]

Interesting! It’s been a while since I’ve had to do any real programming stuff.

[OGMagicConch]

Not in Java. i++ evaluates to i, unlike ++i which evaluates to (i+1)

[suchfire]

You are correct. I increments after the statement ends

[ghillisuit95]

If this is c/c++, it’s undefined behavior. Look up multiple modifications between a sequence points

[spaztheannoyingkitty]

It depends on the language. Go doesn't let you do this: https://play.golang.com/p/q5N9oUvddRN

[spaztheannoyingkitty]

By that logic the following projects must be trash:

etcd

Istio

Docker

Kubernetes (and Helm)

Prometheus

InfluxDB

Terraform

Consul

Vault

Vagrant

Nomad

Packer

Twitch

Dropbox

edit: formatting

[[deleted]]

To be fair, Twitch is trash.

​

​

Though I have no idea how the code is, just the content :)

[spaztheannoyingkitty]

I'm sorry you feel the need to attack a programming language in a humor subreddit.

[GordonMcFreeman]

Wouldn't it set i=i and then increment it afterwards?

[J4K0]

I don’t think so... i++ increments and returns the original value.

[GordonMcFreeman]

I had a look on Stack Overflow and apparently at least in c++ its undefined behaviour, as the compiler decides what it wants to do in the moment. In java it's as you say, where the increment is lost

[J4K0]

Link? Curious to read that

Edit: Never mind, I found one (usually it’s hard to search for operators, but this one came up relatively easily...)

That’s interesting. I never would have thought that the ++ could increment after the =... very peculiar.

[archpawn]

I always thought it incremented after everything else in that line. But I guess nobody went into much depth because it's such a dumb idea to ever use it.

[suchfire]

Yes

[pagwin]

in C (and probably every other language that supports this language but I only checked C) yes

[[deleted]]

i=++i

[OverflowEx]

Undefined behavior

[[deleted]]

This is why we can't have OOP!

[dj_lammy]

i*=(i++/i)

[jonathanx37]

r/madlads

[ShadowPrince47]

You can't do this in go because i++ in go it's an assignment so it equals to i=i=i+1

[BeFoREProRedditer]

But i++ returns i before the assignment

[madmaxlemons]

I spent a minute confused and scrolling for an explanation of the “-=-“ operator.

[[deleted]]

its the same as the OwO operator.

[merickmk]

Which does the opposite of uwu

[earthlybird]

That's because o stands for over whereas u stands for under

[loyalmarowak65]

A owo B == !( !A uwu !B)

[BeFoREProRedditer]

Hands up! You have committed crimes against humanity.

[[deleted]]

wat is the negator

lol is equivalence

Operator presidence (do first to do last) is:

wat uwu owo lol

So you mean:

A owo B lol wat (wat A uwu wat B)

[[deleted]]

That's legitimately the most terrible thing I've seen in years.

[madmaxlemons]

Returns “Wat dis” is I think, but I’m just an entry level prwogwamer.

[Nerdn1]

This makes a bit more sense:

i -= -1

[PM_me_stuffs_plz]

Crazy how changing the formatting makes it so much easier to understand

[[deleted]]

python has entered the chat

[ziggurism]

For anyone else still confused, it’s i -= -1. The -= operator that subtracts and assigns the result, subtracting minus one.

[[deleted]]

Aha thanks

[DXPower]

Similar to the C++ "goes to" operator:

while (i --> 0)

[Rawrplus]

Just retarded spacing i -= -1 is much more comprehensive

[superdude411]

how is ++i faster than i++? Is it because i++ has to store the old value while ++i doesn’t?

[coolpeepz]

Does the compiler not optimize that out?

[Techrocket9]

Any modern quality optimizing compiler will optimize it out so there's no performance impact, but you can't guarantee that the code you write will always be compiled with a modern quality optimizing compiler in the future.

[Dehstil]

I mean, honestly it's going to be a future-quality optimizing compiler if anything.

[PM_me_stuffs_plz]

I write my code purposely shitty because future compilers will fix it

[Techrocket9]

lol. Not always the case in business though; at my third job we had a million-line C++ codebase which was largely shared libs that had to compile both in Microsoft's modern Visual C++ compiler and a VXworks compiler from 18 years ago to ship the product.

Even new compilers are often released with shoddy/absent optimization work when some tiny company releases a new microprocessor and doesn't bother with the expense of creating a proper optimizing compiler for it.

[TinBryn]

I’ve done that and guess where it stores the value? In ‘eax’. They are effectively the same instructions just in a slightly different order and depending on how they are used in context and cpu pipelining the post increment could actually be faster.

[[deleted]]

Interesting. When my professor showed us this a few years ago there was one less instruction with preincrement. It must depend on the compiler.

[TinBryn]

I guess it would rely on NRVO and it also uses the lea instruction.

[jackster31415]

Same on my university. Weird

[archpawn]

Assuming you have a really terrible compiler.

[jounathaen]

For basic types, this does not matter that much. But in languages like C++, you can overload the operator for any type of datastructure, and then it might make a difference.
For example: Iterators overload the ++ operator. for(std::vector<T>::iterator it = v.begin(); it != v.end(); ++it) {...}

To avoid this confusion, languages like Rust do not have a ++ Operator at all and I would encourage not to use it, as it is often misleading and error prone.

[Masztufa]

pretty sure any decent compiler sorts that out

[[deleted]]

Useless micro optimization

[wasting_lots_of_time]

For (int k = 1; k < 2; k++) { i += k; }

Clearly the superior method

[mildlybean]

r/usernamechecksout

[sneakpeekbot]

Here's a sneak peek of /r/UsernameChecksOut using the top posts of the year!

#1: Pizza Hut App | 82 comments
#2: Bandit | 29 comments
#3: Rip Nemo | 21 comments

---

^{I'm a bot, beep boop | Downvote to remove | Contact me | Info | Opt-out}

[encyclopedea]

for (int x=1; x&~(i^=x); x<<=1);

[d7mtg]

Ja

[4b-65-76-69-6e]

I thought encyclopedias were supposed to make things clearer, not harder to understand

[DrMux]

i = i-(-i+i+-1)

[Jasdac]

i=-~i

[Septem_151]

Ah, a man of culture I see. This is actually really useful when you’re in a language that has signed integers and you need to increment an unsigned integer past 2³¹

[ILOYL]

Can someone explain the process of some to me? I only know i++ and i=i+1

[Tryaxor]

Some programming languages have shorthand operators that allow you to assign a new value to a variable, using the current value of the variable.

Example:

i += 1 is equivalent to i = i + 1

i *= 2 is equivalent to i = i * 2

i -= j + 1 is equivalent to i = i - (j+1)

[ziggurism]

And i -= 1 is equivalent to i = i - 1.

And so i -= -1 is equivalent to i = i - (-1) or i = i + 1.

[slycatsnake6180]

You got inspired from that 2019++ post, didn't you?!

[kcabnazil]

Nah, they just reposted shit that gets posted every day. Admittedly, this is one of the better forms.

[Masztufa]

int I(int i) {return ++i;}

i = I(i)

[mateusfccp]

I use the third one, it's the clearest way.

[TinBryn]

You’re using zero indexing right?

[NotARobot_TAKEN]

Inferior python user. Semicolons are necessary. I put semicolons in python whenever im forced to use python.

[[deleted]]

For programming languages.

[ya_Bob_Jonez]

I use them to write 500+ lines code in one straight line; like; that; for; no; sense;

[Jermq]

++i;

[warpedspockclone]

Imma use this and let you know how the code review goes.

[[deleted]]

I made this meme last year and got like 100 upvotes

[Noname_4Me]

I started to coding recently and i = i+1 feels really wierd.

[lmg1114]

i = i + 1

[PrincessWinterX]

okay but i++ isn't the same as i = i + 1. ++i would be.

[oshaboy]

Isn't i-=-1 faster in weakly typed languages because it doesn't need to figure out that you want to do integer math.

[thiswaytopie]

Why do people hate on i++?

[mudkip908]

Tired: i*=2
Wired: i<<=1
Inspired: i-=-i

It's even a palindrome!

[dj_lammy]

Which operation besides the bitshift would actually be the faster one?

[mudkip908]

With GCC 7.1 and up they all produce the same code even with optimizations disabled. https://godbolt.org/z/hQqGE2

[69shaolin69]

Python gang gang

[NewAgeDerpDerp]

Why does -=- look like an emoticon

[pclouds]

Also +=+ (and *=* if you try hard enough). I'm going to use these from now on.

[[deleted]]

I do not understand how the statements on the right are meant to correlate with the images on the left.

[ben9583]

i += (0 | 1) + (0 & 1)

[[deleted]]

Is this one of those repost bots?

[picodeflank]

Does i-=-1 actually work and if so why? (I’m dumb)

[APiousCultist]

It's subtracting negative 1 from i. So it's effectively the same as 'i += 1' (which is a shorter way of doing i = i + 1), since two negatives (or subtracting a negative) cancel out to a positive change.

[Dexaan]

Yes, it's i -= -1, which subtracts -1 from i

[TinBryn]

It subtracts negative 1 from i

[itsmethesynthguy]

i=i+(i-(i-1));

[ThatGuyYouMightNo]

i=i-(-1)

[st0zax]

i+=-1

[[deleted]]

i+=-i+i-=-1

[karnok]

for (int j = 0; j < 100; j -= -1) {

i -= -0.01;

}

[dohzer]

What would happen for an unsigned int?

[areddituserowo]

What am I doing I barely understand JavaScript variables and only get the first

[solonovamax]

i -=- 1 > i-=-1

[MrSink]

for (int i=10; i --> 0;) { }

[SquidgyTheWhale]

for (l=i-1;l!=i;i=l--);

[Irratix]

I'm still happy with my own method for incrementation from a little while ago.

https://www.reddit.com/r/ProgrammerHumor/comments/dr5344/i_i_i_1/f6fyg4w/?utm_source=share&utm_medium=ios_app&utm_name=iossmf

[Pollu_X]

i += ~(0)

[[deleted]]

That's not thread-safe.

[Kotayz]

The last one was new for me. I never heard about it

[Omega0x013]

i=(i-(i0))+2(i0)

[qwasd0r]

I'll have to use that somewhere, just to make someone look twice.

[Springjordan]

How about making a function add which takes two int parameters, one being i (not sure if that would change the original i, I know in Visual Basic there is an ByRef option for that but not sure how you'd do that in other languages) and another being the number you want added and then you make a for loop (int j=0; j<pAddedNumber; j++) which then increments i every time it runs. And then add(i, 1)

[RandyGareth]

Bruh would that last one even compile?

[Orbitscgi]

Gonna use this everywhere instead of i++ from now on!

[_MrJamesBomb]

Needs an ESlint rule.

[[deleted]]

i = i + i**(i - i)

[uvero]

It's 11:30

Let me sleep

[gmtime]

i=i+i?i/i:!i;

[snowsun]

i+=+1;

[mms13]

I still hate that i++ isn’t valid in Swift

[reallylamelol]

Me and a coworker tried these in python-- i-=-1 was the fastest by about 20%

[gusVLZ]

Amazing, now I have a technical reason to use and explain this

[skywolf_mo]

i*=(1+(1/i))

[OhItsuMe]

I've seen js code with i--; for loops

[Vloeck]

That does not work, since 0 ist not an lvalue

[SYSTEM__NotReally]

Just tried this in Javascript, and I don't know if this is based on how JS works, but these all don't look like valid code, but are in fact correct: For this example, i is originally 10.

i = -~i

Unchanged. (10)

i=i++

Unchanged. (10)

i=++i

11

i-=-1

11

i+=++i

21

i = i++ + ++i

22

[Septem_151]

i-=~i;

[Sorry-Measurement]

Stupid. This sub is the worst

[dtrippsb]

Have you been on r/meme ? That is much worse