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Better C++ / Chicago July 12-14, 2017

By Jason Turner | May 23, 2017 09:48 AM | Tags: performance intermediate basics

Join us for a 3 day training event in Chicago, IL, USA July 12-14, 2017

Better C++ / Chicago

by Jason Turner

About the training:

Through this training you will gain a better understanding of how to write clean, maintainable, and well performing C++ code.

The topics covered apply to all types of C++ development: embedded, system or application development.

Jason's classes are highly interactive and have a limited class size to ensure that everyone has sufficient opportunity to participat

A la carte tickets are available for those wishing to attend only part of the training.

Wednesday: Demystifying C++11 and Beyond

C++11, 14, and 17 added many new features to C++ that have made many question the overhead of using these new features and the complexity they add to the language. We will make an in depth examination of these features to give you confidence in using and deploying modern C++ techniques in your organization.

Thursday: Understanding Object Lifetime in C++

C++ has what very few other languages have: a well defined object life cycle. Understanding this key aspect of the language is critical for writing high quality C++.
We will describe the lifecycle of an object in C++ and work through increasingly complex examples. There will be something for C++ developers of all skill levels to learn.

Friday: C++ Best Practices

On the final day of the course we will cover a series of tangible best practice rules for how to write C++ code that is maintainable and efficient by default.
We will wrap up with a discussion of how to use the tools available to maintain code quality.

Quick Q:Is there a way to mark a parent's virtual function final from a child class?

By Adrien Hamelin | May 4, 2017 01:05 PM | Tags: c++11 basics

Quick A: No.

Recently on SO:

Is there a way to mark a parent's virtual function final from a child class without reimplementing it

No, you can't do it without reimplementing it. So just reimplement it:

struct Child : public Parent
{
    virtual void fn() override final { Parent::fn(); }
};

N.B. saying virtual ... override final is entirely redundant, final is an error on a non-virtual function, so you should just say:

    void fn() final { Parent::fn(); }

See http://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#Rh-override

Quick Q: shrink_to_fit() vs swap trick

By Adrien Hamelin | May 2, 2017 01:47 PM | Tags: c++11 basics

Quick A: Are equivalent, but shrink_to_fit mark the intention.

Recently on SO:

shrink_to_fit() vs swap trick

The swap trick isn't actually constant-time. The cost of performing the actual swap is indeed O(1), but then there's the cost of the std::vector destructor firing and cleaning up all the allocated space. That can potentially have cost Ω(n) if the underlying objects have nontrivial destructors, since the std::vector needs to go and invoke those destructors. There's also the cost of invoking the copy constructors for all the elements stored in the initial vector, which is similarly Ω(n).

As a result, both approaches should have roughly the same complexity, except that shrink_to_fit more clearly telegraphs the intention and is probably more amenable to compiler optimizations.