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Hi friends how to create our own header file?

Isn't first one requires is requires-clause and the second one is requires-expression?

#ot

/get cppbookguide

C++20 has has me me seeing seeing double double #prog #cpp twitter.com/slurpsmadrips/status/1266080792012140545

😂😂

hey im taking a class in mutithreaded programming and i have an exercise where i dont have any clue to what i should calculate there.

if somebody could tell me what is meant by average delay there that would be great :)

What i did for now is just to program both cases out and perform benchmarks for various things lilk the total computing time, the time it takes to switch threads etc. but when i had a second look this doenst seem to be what was asked for

Isn't first one requires is requires-clause and the second one is requires-expression?

Yes, but if you're going to use a requires-xpression along with a requires-clause, you'd better define a concept for that requires-expression

For example, I'd do: template <typename T> concept dereferenceable = requires (T t) { t.dereference(); };

Yeah, that's what I'm saying

For me it's more readable defining a concept than using an inline requires-expression

Ohhhh thanks. Got that completely wrong

Yeah that isnt possible unfortunately :/. But thats the way i saw it at first but that would be the administration time right? And in the exercise there is stated that we should ignore that. But since i already calculated that i can inclufe that as well as a footnote. Again thank you so much for your 1st interpretation. I think that is what he meant :)

/ban @KMRSOFT_9 python + ad + not approved + read the rules

I warned you already, but python people can’t read it seems

Is this work on mac os, but it isn’t work on windows, why is that? https://paste.ubuntu.com/p/ZrHSCkCGTb/ studentx txt file is 8 line, in windows loop just one cycle

maybe because of file format?

Is this work on mac os, but it isn’t work on windows, why is that? https://paste.ubuntu.com/p/ZrHSCkCGTb/ studentx txt file is 8 line, in windows loop just one cycle

in windows just created blabla.txt, and text file is empty

I mean next lines etc

I mean next lines etc

same file both

File is this

File is this

windows just created VIANNEY.txt and it’s empty. Mac os 8 files created

These are other files

Say hi if I r not dumb

Код: template <typename T> void foo (T arg) requires { arg.method(); } {} Компилятор (GCC 10.1 с -std=c++20): source>:2:10: error: missing additional 'requires' to start a requires-expression 2 | requires { arg.method(); } | ^ | requires Так что тот товарищ неправ

↑

Which parenthesis?

int main(int argc, char **argv) { return argc; }

Done what was so difficult?

If you want to avoid a compiler warning

int main(int argc, char **argv) { (void)argv; return argc; }

template <typename T> void foo (T arg) requires arg.method(); {} vvv <source>:2:13: error: use of parameter outside function body before '.' token 2 | requires arg.method(); | ^ <source>:2:13: error: expected initializer before '.' token <source>:3:1: error: expected unqualified-id before '{' token 3 | {} | ^

I think this is the way when defining a concept, as there's no variable name yet, in contrast with a function, where you already have the argument name

template <typename T> void foo (T arg) requires (T arg) { arg.method(); } {} vvv <source>:2:13: error: expected primary-expression before 'arg' 2 | requires (T arg) { arg.method(); } | ^~~ <source>:2:12: error: expected ')' before 'arg' 2 | requires (T arg) { arg.method(); } | ~ ^~~~ | )

Do you guys know any high-level crypto libraries usable with C++ that have decent documentation?

GPGME's is lacking in examples

Is there any short way to prepend to a string without using a second variable?

Is there any short way to prepend to a string without using a second variable?

str_to_prepend_to.insert(0, prefix)

str_to_prepend_to.insert(0, prefix)

error: request for member 'insert' in something not a structure or union

error: request for member 'insert' in something not a structure or union

So you are using C, right? And you're talking about const char*, right?

Then you have to use strcat

Then you have to use strcat

But it's for appending. I want to prepend.

But it's for appending. I want to prepend.

You can shift right as many positions as characters are in the string you want to prepend in the original string, and then do a memcpy

The problem is if b is not a variable but a pure c-string

For example, doing strcat(str, str2); or strcat(str2, str); is okay, but strcat(str, "Some string"); is okay while strcat("Some string", str); is a compile error

For example, doing strcat(str, str2); or strcat(str2, str); is okay, but strcat(str, "Some string"); is okay while strcat("Some string", str); is a compile error

Yeah this. Like I said, there's no involvement of any second variable.

For example, doing strcat(str, str2); or strcat(str2, str); is okay, but strcat(str, "Some string"); is okay while strcat("Some string", str); is a compile error

Yes because a string literal is const char *

You can't exactly edit it

Nothing different from what @fgallego96 said. char st[100] = "world"; char st1[10]= "hello "; Trying to prepend so that st stores "hello world". Cannot append to st1 because it's too small.

Nothing different from what @fgallego96 said. char st[100] = "world"; char st1[10]= "hello "; Trying to prepend so that st stores "hello world". Cannot append to st1 because it's too small.

As I said, shift right as many elements as you need in the string you want to copy into, and then do a strcpy

As I said, shift right as many elements as you need in the string you want to copy into, and then do a strcpy

Yeah that's one way. I was just looking for something short.

I guess in the memmove you wanted to write strlen(st1), am I right?

Okay

Okay thanks

/get ide

Hey everyone. Is there a reasonable way to store sensitive data in memory?

/get eBook

/get cbook

Hey everyone. Is there a reasonable way to store sensitive data in memory?

Encryption

Encryption

On memory? I'll store user password.

On memory? I'll store user password.

Yes. If the data in sensitive, and you don't want people to read it easily, your best option is to encrypt the data, so a potential attacker can't get the original message without masive computational power

Yeah, thanks. Does OpenSSL AES objects store keys encrypted?

I have no idea because I haven't used it, but OpenSSL is pretty common in security stuff, so you may find what you want in the official documentation

Yeah, thanks. Does OpenSSL AES objects store keys encrypted?

I couldn't decide if memory encryption worth the effort or not. If OpenSSL stores the key in plaintext it has no meaning...

I couldn't decide if memory encryption worth the effort or not. If OpenSSL stores the key in plaintext it has no meaning...

The point is not where it is stored, but how. It may be stored in plaintext (as everything in an OS), but is not the same storing "my_password1234" as "vnu93n0b4h", for example

How does if constexpr really works internally?! Is there any generation of function when the second constant boolean expression takes a new branch?

How does if constexpr really works internally?! Is there any generation of function when the second constant boolean expression takes a new branch?

It generate a branch only when it's used

When it's not used it can ill-formed code of some kind (not too much ill-formed)

When it's not used it can ill-formed code of some kind (not too much ill-formed)

I mean If two branches are meant to be generated Does that mean one function has a two set of instructions for execution determined at compile-time?!

Is that even possible It's like saying:"I'm bad but Good"

I mean If two branches are meant to be generated Does that mean one function has a two set of instructions for execution determined at compile-time?!

I think there just two separate functions

Because if constexpr is just а good-looking sfinae

I think there just two separate functions

Yeah The only logical explanation I can think of Two overloaded functions

Because if constexpr is just а good-looking sfinae

And it eases the use of variadic templates

Past you need to overload the function in a recursive manner