this post was submitted on 05 Apr 2025
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Programmer Humor

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[–] SpaceNoodle@lemmy.world 46 points 1 week ago* (last edited 1 week ago) (1 children)

If I'm writing C++, I'm usually optimizing for portability over performance, in which case I would prefer std::endl as it would yield the best results regardless of platform; it also keeps the end-of-line character out of other strings, making code just a little cleaner.

\n is for when I'm done pretending that anything that isn't Unix-like is OK, or I'm counting the cycles of every branch instruction.

[–] barubary@infosec.exchange 32 points 1 week ago (2 children)

std::endl provides zero portability benefits. C++ does have a portable newline abstraction, but it is called \n, not endl.

[–] Albbi@lemmy.ca 49 points 1 week ago

Thank you two for demonstrating the image in the post so well.

[–] SpaceNoodle@lemmy.world 7 points 1 week ago (1 children)

No, there's no guarantee that in every context \n is translated portably.

[–] barubary@infosec.exchange 15 points 1 week ago (2 children)

The same is true of std::endl. std::endl is simply defined as << '\n' << std::flush; nothing more, nothing less. In all cases where endl gives you a "properly translated" newline, so does \n.

[–] SpaceNoodle@lemmy.world 6 points 1 week ago (1 children)

Ahhh, I see. Looks like the magic happens somewhere further down in iostream.

[–] AnyOldName3@lemmy.world 3 points 1 week ago

It's controlled by whether the stream's opened in text mode or binary mode. On Unix, they're the same, but on Windows, text mode has line ending conversion.

[–] zenforyen@feddit.org 2 points 1 week ago

Yeah it's an artificial dichotomy based on a popular misconception of what std::endl is and how \n is interpreted.

Ultimately it does not ask about line endings, but about flushing, which is a completely orthogonal question.

[–] jecxjo@midwest.social 21 points 1 week ago (2 children)

They aren't the same thing so the comparison is weird.

endl has a flush which is important when doing something like embedded work or RTOS development. If i was doing multiple lines they all were \n until the last line when i actually want to push the buffer.

Obviously depending on the tuning of the compiler's optimization multiple flushes could be reduced but the goal should always be to write as optimal as possible.

[–] aport@programming.dev 3 points 1 week ago (2 children)

Who in the hell is using iostreams in an RTOS

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[–] lud@lemm.ee 3 points 1 week ago

but the goal should always be to write as optimal as possible.

Within reason.

Over optimization is a curse on getting done.

[–] UpperBroccoli@lemmy.blahaj.zone 19 points 1 week ago

\n, because I ordered a newline, not a flush.

[–] unlawfulbooger@lemmy.blahaj.zone 17 points 1 week ago (5 children)
[–] vapeloki@lemmy.world 40 points 1 week ago (1 children)

std::endl is used in output streams in C++ to end the line, using the os specific line termination sequence, and flush the buffer.

The later one is a performance issue in many cases, why the use of "\n" is considered preferred

[–] xigoi@lemmy.sdf.org 2 points 1 week ago (2 children)

Don’t most terminals flush the buffer on newline anyway?

[–] ClemaX@lemm.ee 7 points 1 week ago

It is the stream itself that is buffered, so the terminal does not handle the contents until the stream is flushed.

[–] vapeloki@lemmy.world 2 points 1 week ago

Maybe, but there is the internal buffer. Also, most I/O happens in files not consoles

[–] hellfire103@lemmy.ca 10 points 1 week ago* (last edited 1 week ago) (5 children)

Instead of this:

std::cout << "Hello world.\n";

You can do this:

std::cout << "Hello world." << endl;
[–] Daedskin@lemm.ee 5 points 1 week ago

The fact that you used the namespace for cout but not for endl inordinately bothers me

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[–] gon@lemm.ee 7 points 1 week ago (2 children)
[–] unlawfulbooger@lemmy.blahaj.zone 11 points 1 week ago (2 children)

Boy am I glad I don’t do C++ anymore. That string handling with the overloaded bitshift operator was wild.

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[–] allywilson@lemmy.ml 3 points 1 week ago

From memory it's a way to declare a line ending after your string.

[–] jaybone@lemmy.zip 2 points 1 week ago

God bless your soul.

[–] GideonBear@lemmy.ml 15 points 1 week ago

#define endl "\n"

[–] scrubbles@poptalk.scrubbles.tech 11 points 1 week ago (1 children)
[–] tourist@lemmy.world 9 points 1 week ago
/* I'm new to this language so just imagine there is a new line here when it prints: */
[–] besselj@lemmy.ca 10 points 1 week ago (2 children)
[–] SpaceNoodle@lemmy.world 20 points 1 week ago (1 children)
[–] xmunk@sh.itjust.works 3 points 1 week ago

Yeah \r gang4lyfe

[–] aport@programming.dev 2 points 1 week ago (1 children)

Are you a modem by any chance?

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[–] lengau@midwest.social 9 points 1 week ago

os.linesep

Lol jk none of my stuff runs on Windows anyway

[–] xmunk@sh.itjust.works 8 points 1 week ago (1 children)
[–] grandel@lemmy.ml 2 points 6 days ago (1 children)

I like that you added the absolute namespace identifier or whatever its called

[–] xmunk@sh.itjust.works 1 points 6 days ago

I don't always namespace but when I do I fully qualify.

[–] nope@jlai.lu 5 points 1 week ago (2 children)

Environment.NewLine might exist in C#

[–] MrScottyTay@sh.itjust.works 2 points 1 week ago

It might do. I encountered it last week as I needed it for a powershell script. So it exists in that at least

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[–] savvywolf@pawb.social 5 points 1 week ago
[–] pewpew@feddit.it 5 points 1 week ago
[–] bramen49@lemmy.ml 4 points 1 week ago

Well, Java has System.lineSeparator so, maybe no?

[–] lnxtx@feddit.nl 4 points 1 week ago

Rebel side \0

[–] dave@feddit.uk 3 points 1 week ago
[–] RandomVideos@programming.dev 2 points 1 week ago

Endl is faster to type

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