By Meeting C++ | Oct 22, 2019 04:58 AM | Tags: meetingcpp intermediate events conference community c++17 c++14 c++11 basics
Some details on the keynotes of this years Meeting C++ conference
Keynote details for Meeting C++ 2019
by Jens Weller
From the article:
With just a few weeks left to Meeting C++ 2019, its time for a closer look at the keynotes!
By Meeting C++ | Sep 9, 2019 12:48 AM | Tags: meetingcpp efficiency conference community basics advanced
Also available in this year: the programs for students and diversity & support for Meeting C++ 2019
Highlighting the Student and Support Tickets for Meeting C++ 2019
by Jens Weller
From the article:
With the Schedule for Meeting C++ 2019 being complete regarding submitted talks, I want to highlight, that there is an opportunity for folks to attend the conference with a free ticket!
By Adrien Hamelin | Sep 6, 2019 11:00 AM | Tags: c++11 basics
Quick A: it is not possible
Recently on SO:
Removing item from vector, while in C++11 range 'for' loop?
No, you can't. Range-based for is for when you need to access each element of a container once.
You should use the normal for loop or one of its cousins if you need to modify the container as you go along, access an element more than once, or otherwise iterate in a non-linear fashion through the container.
For example:
auto i = std::begin(inv); while (i != std::end(inv)) { // Do some stuff if (blah) i = inv.erase(i); else ++i; }
By Adrien Hamelin | Sep 5, 2019 11:41 AM | Tags: basics
Quick A: default constructors are called if available, otherwise there is no initialisation.
Recently on SO:
How do C++ class members get initialized if I don't do it explicitly?
In lieu of explicit initialization, initialization of members in classes works identically to initialization of local variables in functions.
For objects, their default constructor is called. For example, for std::string, the default constructor sets it to an empty string. If the object's class does not have a default constructor, it will be a compile error if you do not explicitly initialize it.
For primitive types (pointers, ints, etc), they are not initialized -- they contain whatever arbitrary junk happened to be at that memory location previously.
For references (e.g. std::string&), it is illegal not to initialize them, and your compiler will complain and refuse to compile such code. References must always be initialized.
So, in your specific case, if they are not explicitly initialized:
int *ptr; // Contains junk string name; // Empty string string *pname; // Contains junk string &rname; // Compile error const string &crname; // Compile error int age; // Contains junk
By Adrien Hamelin | Aug 5, 2019 12:42 PM | Tags: basics
Quick A: optimisation compilers are allowed to do for perfomance.
Recently on SO:
What are copy elision and return value optimization?
Copy elision is an optimization implemented by most compilers to prevent extra (potentially expensive) copies in certain situations. It makes returning by value or pass-by-value feasible in practice (restrictions apply).
It's the only form of optimization that elides (ha!) the as-if rule - copy elision can be applied even if copying/moving the object has side-effects...
By Adrien Hamelin | Jul 11, 2019 12:43 PM | Tags: basics
Quick A: in the order of declaration in the class.
Recently on SO:
Constructor initialization-list evaluation order
It depends on the order of member variable declaration in the class. So a_ will be the first one, then b_ will be the second one in your example.
By Adrien Hamelin | Apr 25, 2019 07:59 AM | Tags: basics
Quick A: No.
Recently on SO:
Does the default constructor initialize built-in types?
Implicitly defined (by the compiler) default constructor of a class does not initialize members of built-in types.
However, you have to keep in mind that in some cases the initialization of a instance of the class can be performed by other means. Not by default constructor, nor by constructor at all...
By Meeting C++ | Apr 25, 2019 05:09 AM | Tags: performance meetingcpp experimental efficiency community c++20 c++17 c++14 c++11 basics advanced
The call for submissions is open for Meeting C++ 2019!
New speakers are welcome to submit as there is a dedicated track for this, start speaking at Meeting C++!
Submit your talk to Meeting C++ 2019!
by Jens Weller
From the article:
When Meeting C++ 2019 was announced in the begin of April, there was already a hint that you could submit your talks. And so far a few have done so. Now its time for an official news entry. Submit your talk to Meeting C++ 2019! This year its the 8th edition of Meeting C++!
Speaking at Meeting C++ is a fun experience, you get to attend the speakers dinner, attend the full conference for free and enjoy the luxurious Hotelrooms the Andels offers from Wednesday to Saturday! You can look at last years schedule to get a feel for what your competition might talk about, but have in mind that you don't see the talks that were not submitted! If you want to talk about a C++ topic that wasn't covered yet, or have a unique idea for your talk, please submit! Speakers don't need to buy a ticket and the conference has a contingent of rooms available for speakers & staff.
By Adrien Hamelin | Mar 21, 2019 12:19 PM | Tags: community basics
Their usefulness dwindles with time.
Macro Evil in C++ Code
by Andrey Karpov
From the article:
The C++ language opens extensive opportunities to go without macros. So let’s try to use macros as seldom as possible!
By Adrien Hamelin | Mar 19, 2019 11:42 AM | Tags: c++11 basics
Quick A: A convenient way to create a functor.
Recently on SO:
What is a lambda expression in C++11?
C++ includes useful generic functions like std::for_each and std::transform, which can be very handy. Unfortunately they can also be quite cumbersome to use, particularly if the functor you would like to apply is unique to the particular function.
#include <algorithm> #include <vector> namespace { struct f { void operator()(int) { // do something } }; } void func(std::vector<int>& v) { f f; std::for_each(v.begin(), v.end(), f); }If you only use f once and in that specific place it seems overkill to be writing a whole class just to do something trivial and one off...