I use g++ on Ubuntu

I know what's in it, but I'd like to find the concrete numbers :)

what about sizeof?

what about sizeof?

It doesn't work that way

I use g++ on Ubuntu

https://github.com/gcc-mirror/gcc/tree/master/libstdc%2B%2B-v3 Probably this one

It doesn't work that way

why?

why?

Because you have no access to the control block type

https://github.com/gcc-mirror/gcc/tree/master/libstdc%2B%2B-v3 Probably this one

Thank you! Now to read some very complicated source code 😂

Waw, that sounds like one way to do it yeah... All I could find so far is the shared and weak counters are atomic words

I mean size wise, that it's two words

Thanks! Didn't know that

Mmmm, I think it's the size of an int though

I thinkkkk my curiosity isn't so strong actually 😂 I'm just glad I went with my own reference counting rather than shared_ptr

I'm reinventing the wheel because I know I won't use weak pointers, I know it's single-threaded, I know I'll never have more than 255 copies, so it's not too complex to implement

It has reduced the size of my most passed around object from 24B to 8B per reference and other memory I was trying to find out

so skinny, fast :) I'm unsure about your second question though

It's not, I'm writing a VM for a programming language I'm making

I'm just afraid of getting it wrong, I'm not a very strong C++ programmer. I've covered the "big 3", construction, copying, assignment, and then destruction

I'm just afraid of getting it wrong, I'm not a very strong C++ programmer. I've covered the "big 3", construction, copying, assignment, and then destruction

You need to cover "big 5": 1) default constructor 2) copy constructor 3) copy assignment 4) move constructor 5) move assignment

Ohhhh, thank you

Though I've never actually used std::move before, I suppose that's what 4/5 refer to?

Could someone recommend me a tutorial or book about bootloader?

You didn't read the pinned message

In the example: Class Entity { // }; Entity e; e= Entity (8) string s = "stringval" ;

Can some one help me with CS and Data science??

In the example: Class Entity { // }; Entity e; e= Entity (8) string s = "stringval" ;

Why we pass value to object ....typecasting value (8) with class name......but for string directly pass the string?

Why we pass value to object ....typecasting value (8) with class name......but for string directly pass the string?

String has implicit constructor from const char*

In the example I can directly pass integer value like : Entity e= 8;

So what's the point of typecasting integer value with class name like ( Entity (8) )

So what's the point of typecasting integer value with class name like ( Entity (8) )

read about explicit constructor in c++

Okie will check

So what's the point of typecasting integer value with class name like ( Entity (8) )

To be clear with type maybe

std::map<unsigned int, const cmap_t&> cmap_cache; this works const cmap_t &v = cmap_cache.at(5); this produces lots of template compilation errors const cmap_t &v = cmap_cache[5]; I suspect this is about reference forwarding. does anybody know?

std::map<unsigned int, const cmap_t&> cmap_cache; this works const cmap_t &v = cmap_cache.at(5); this produces lots of template compilation errors const cmap_t &v = cmap_cache[5]; I suspect this is about reference forwarding. does anybody know?

You cannot store references in std containers

Use pointers or reference_wrapper

You cannot store references in std containers

https://stackoverflow.com/questions/24719044/unordered-map-with-reference-as-value

std::map<unsigned int, const cmap_t&> cmap_cache; this works const cmap_t &v = cmap_cache.at(5); this produces lots of template compilation errors const cmap_t &v = cmap_cache[5]; I suspect this is about reference forwarding. does anybody know?

operator[] requires value type to be default constructible, references are not

Edited

You cannot store references in std containers

that's also not completely true

operator[] requires value type to be default constructible, references are not

thank you.

that's also not completely true

Yeah, my mistake, didnt know its a thing

#ot

It's okay Danya, don't have a spite against me 😃

if i have mpzt array i hava to inits all elements?

mpzt?

is bad way free pointer inside loop?

is it wrong to free pointer memory inside a loop? because if I free the memory after the loop, some of the information will be overwritten instead of being freed.

Anyone have a question bank for competitive programming on DSA..?

Hi, please somebody understand the use of two assert her👆

Hi good day, I need help.. I am trying to use the wampcc library in a Qt application. Qt version: QtEmbedded-4.8.6-arm Toolchain: 4.9.3 (arm-cortexa9-linux-gnueabihf) But when compiling, many errors appear: 4.9.3 / chrono: 221: 6: error: macro "max" requires 2 arguments, but only 1 is provided Checking chrono the error it is inside the block "#ifdef _GLIBCXX_USE_C99_STDINT_TR1" which is not defined. Any idea of ​​the problem?

My problem is similar to the one posted at https://stackoverflow.com/questions/55364206/qt-5-8-compile-issues-with-stdchrono

In the code: Class Complex{ Public: Double real Double imag; Bool operator==(Complex rha){ Return(real ==rha.real && imag==rha.imag)? True:false; } }; Int main(){ Complex com1(3.0,3.0); If(com1== 3.0) //Do something

My doubt here is......if we calling overloaded operator as (com1==3.0)....we should insert two arguments into the overloaded function declaration right? One the object com1 and other is the number may be?

What I don't understand -> how we decide what goes inside operator overloading function's arguments while declaring

Do not directly include any header files that do this. I did a test compiling an example of using the wampcc library without using Qt and using the same toolchain and it compiles without problem. So I think it has to do with Qt.

yes, is chrono lib. Ok, I search in the Qt headers.

Guess I want to overload this operator (<<) left shift operator to print string class obj like: Cout<<string (string header file not included)

So in defination Class string{ Public: Char *str; String& operator<<( const string& other) { //Here is passing just the string //obj is sufficient enough to print the string....as overloaded func is now a class member? } };

Calling this as - String s = "xyz"; Cout << s;

Yeah that's what I understand.....so the question again come down to how will I decide what all goes inside the overloaded func arguments?

Like the operator is written between two operands? So do I need

To pass those two operands as arguments

I looked in the entire QtEmbedded-4.8.6-arm folder and did not find that definition. I only found it in 2 files but from the ..toolchain/4.9.3 .. /opt/scv/toolchain/4.9.3/arm-cortexa9-linux-gnueabihf/sys-root/usr/include/sys/param.h /opt/scv/toolchain/4.9.3/lib/gcc/arm-cortexa9-linux-gnueabihf/4.9.3/plugin/include/system.h

I'm new to C, where should i start learning Any tips guys

I understand overloaded func being class member and outside class logic....I was struggling for for urinary and binary operators

Will check some examples on that

Btw just one thing.... can't a unary operator be overloaded as a binary operator func?

Cool....that's clear the confusion ... thanks 👍

Ok, one question.. I understand that a code block that is inside of #ifdef, is only compiled if the value is defined, is it correct? I ask why the lines where the error indicates is inside a block, which if value is not defined (#ifdef _GLIBCXX_USE_C99_STDINT_TR1).

I don't understand why if _GLIBCXX_USE_C99_STDINT_TR1 is not defined, the errors appear?

I don't understand why if _GLIBCXX_USE_C99_STDINT_TR1 is not defined, the errors appear?

Maybe is better to search for Google

In the following code: Class Entity { Public: Entity(int x){} Entity(const string & s){} }; Int main() { Entity e= 5;. //valid Entity s= "value";. //not valid?? //Needed to Entity s= Entity("value");

Here in example why I no need to typecast the integer while passing to object

But need to typecast string value to pass to object???

I have already read a quite some stuff on c++..... cannot understand typecasting here

As most of the implicit conversation takes place for string object

Yeah that solves the confusion 👍

But then: Entity e1= "value";. //Invalid for obvious reasons Entity e2(" value") ; works fine for some reason

How const char* "value" passed in second case get converted to string object there

Ok got it's.....seems like copy intiliazation is intializing a object Entity e1 with another object "value"(const char*)....so that we need to explicitly typecast "value" here to Entity type