You should not modify the object in operator+
It modifies the current (lhs) object. Because the objection is to add the rhs object to it.
Azadi
Danya🔥
It modifies the current (lhs) object. Because the objection is to add the rhs object to it.
a + b
Do you expect a to be changed in this expression?
Mehrad
a + b
Do you expect a to be changed in this expression?
i agree
when you write something as method form it does not mean your must modify the caller method object
Ehsan
It modifies the current (lhs) object. Because the objection is to add the rhs object to it.
This is how you do it correctly:
T operator+(const T& rhs) const {
T result = *this;
// add rhs to result
return result;
}
Mehrad
Hi all. Overloading operator+ inside the class should I make a new copy inside, populate and return it, or directly modify "this" and return "this"?
Which approach is preferable?
also it's better to write as helper func in order to have implicit converstions
Danya🔥
also it's better to write as helper func in order to have implicit converstions
It's not better to have implicit conversions
Ehsan
What you did is modify the operand and also you don't really add anything you are just returning *this unmodified, also it will cause problems if the two added objects are the same
Azadi
a + b
Do you expect a to be changed in this expression?
No, you're right. I confused it with += operator.
Danya🔥
What does that suppose to mean?
Implicit conversions are part of the language we call C++ and are mandated by the standard, so they behave exactly the same everywhere expect the compiler bugs
But I don't think there are a lot of bugs related to them because it's the core of language from the very beginning.
Mehrad
Because implicit conversions are error-prone
so you need use explicit keyword for every type that has been decalared
Danya🔥
so you need use explicit keyword for every type that has been decalared
For almost every type yeah
You should mark all the single parameter constructors explicit of almost all types
This should be the default way to write code
And you have to put a lot of consideration on removing the keyword for the specific use of it
Ehsan
Implicit conversions are part of the language we call C++ and are mandated by the standard, so they behave exactly the same everywhere expect the compiler bugs
But I don't think there are a lot of bugs related to them because it's the core of language from the very beginning.
Hmmm really? Then why gcc sometimes doesn't make warning on some implicit conversions? Even with Wall?
Danya🔥
Hmmm really? Then why gcc sometimes doesn't make warning on some implicit conversions? Even with Wall?
Warnings are not mandated by the standard
Danya🔥
Only the feature itself
Ehsan
I see thanks for the info
AlanCcE
If your talking about Data Science you should use Python
Manuel
If your talking about Data Science you should use Python
Why not bringing data science back to C?
Manuel
could be used for data science on the edge, on IoT devices etc.
Danya🔥
what's wrong on using C for data science
The right question is "what's wrong on using C"
And the answer is "everything"
Manuel
if it was possible to use Fortran on embedded devices it would be even better, but C is already very efficient
klimi
Manuel
Morocos
Why is Fortran better than C?
Danya🔥
But both languages are not great
Manuel
Why is Fortran better than C?
Better at dealing with vector, matrices etc. due to its memory management (essentially the reason why Lapack etc. have been developed in Fortran)
Danya🔥
if it was possible to use Fortran on embedded devices it would be even better, but C is already very efficient
Why do you need data science on such edge where you can't even use Fortran?
Danya🔥
Isn't the better solution to do this on more capable hardware?
Manuel
because 1) it's faster (no network latency for bringing the data on the cloud) 2) it's more energy efficient 3) more reliable and 4) those are resources that are yet under-utilized
Danya🔥
because 1) it's faster (no network latency for bringing the data on the cloud) 2) it's more energy efficient 3) more reliable and 4) those are resources that are yet under-utilized
What kind of hardware is it? Microcontrollers like Pi Pico?
Manuel
like esp32, like stm, like many things
Azadi
This is how you do it correctly:
T operator+(const T& rhs) const {
T result = *this;
// add rhs to result
return result;
}
Yes, it's one of the ways for that purpose and likely one of the easiest things I'm dealing with in C++ on a daily basis. But the shit issue happens when you see + as +=.
klimi
what's bad on calculating the mean in C?
AlanCcE
Why not bringing data science back to C?
It's nice as hobby or as way of learning something different, but if his intention is to work with it it's better to do it in Python
Manuel
It's nice as hobby or as way of learning something different, but if his intention is to work with it it's better to do it in Python
I am not sure, data science in Python in pretty crowded and reaching its limits
AlanCcE
When was C used for data science?
A long time ago some people used to do some really badass stuff in Data Science, people in old days were like mages haha
Danya🔥
A long time ago some people used to do some really badass stuff in Data Science, people in old days were like mages haha
I don't think so
Most of the science computing was performed in Fortran
Danya🔥
Yet it's offtop
AlanCcE
I am not sure, data science in Python in pretty crowded and reaching its limits
Your right! But he has freedom to try it I think, if it's really his interest
𝔖𝔞𝔯𝔬
I don't think so
Most of the science computing was performed in Fortran
Lots of people miss Fortran
Manuel
(don't get me wrong, I have been teaching data science in Python, I am not against it, but now every kid and his grand-ma can do a .fit() and .predict() with scikit-learn)
Manuel
Depends how much you pay me 😆
Danya🔥
Do the business outside of this chat
Chat Boss
Hi all. Overloading operator+ inside the class should I make a new copy inside, populate and return it, or directly modify "this" and return "this"?
Which approach is preferable?
Azadi sent a code, it has been re-uploaded as a file
Azadi
Is sending code disallowed here?
Houdaifa
Question about memory managment
When you quit a program how the OS can know what memory spaces to free ?
In the case when you declare variables on the runtime and lose thier adress
Danya🔥
Question about memory managment
When you quit a program how the OS can know what memory spaces to free ?
In the case when you declare variables on the runtime and lose thier adress
Because OS allocates the memory and then gives you the pointer
Danya🔥
What does "declare variables on the runtime" mean?
Houdaifa
What does "declare variables on the runtime" mean?
using "new" or "malloc"
Danya🔥
using "new" or "malloc"
It's not related to variable declaration whatsoever
Houdaifa
Because OS allocates the memory and then gives you the pointer
so the OS have a copy of all the pointers ?
XOFF
You dont declare a var when calling new or malloc
XOFF
In a way…
XOFF
OS has your virtual memory page
Danya🔥
OS manages all the resources pf your process: memory, files, pipe, you name it
It's one of the essential characteristics of OS
Houdaifa
It's not related to variable declaration whatsoever
I mean by that it is obvious in the case of static and global and local variables because it is esay to group them and free them
but when you are using linked list the memory is not consecutive so the OS in this case must store every pointer and I think this is a lot of wasted space
Danya🔥
I mean by that it is obvious in the case of static and global and local variables because it is esay to group them and free them
but when you are using linked list the memory is not consecutive so the OS in this case must store every pointer and I think this is a lot of wasted space
Local and global variables are not freed by os but by the program itself
XOFF
My friend you should look for fragmentation, paging, memory pools and memory managements
Houdaifa
My friend you should look for fragmentation, paging, memory pools and memory managements
can you give me some good resources for this ?
Houdaifa
I learn this from wikipidia and I feel I am far from understanding it
XOFF
Unfortunately i would do the same thing you would basic Google search and reading lots of stack over flow posts
Houdaifa
Unfortunately i would do the same thing you would basic Google search and reading lots of stack over flow posts
there is no need for books ?
XOFF
Nope if you dont need deep understanding