Home » Blog » Tags » intermediate

intermediate

Introduction To the C++11 Feature: Extended friend Declaration -- FangLu

By Blog Staff | May 6, 2013 11:26 PM | Tags: intermediate basics

Head on over to the C/C++ Cafe for:

Introduction to the C++11 feature: extended friend declaration

by FangLu

Excerpt:

The extended friend declaration feature is newly introduced in the C++11 standard. In this article, I will introduce this feature and provide some examples on how to use this feature.

 

Firstly, let's see why this feature is added into C++11. ...

 

GotW #1: Variable Initialization—or Is It? -- Herb Sutter

By Blog Staff | May 6, 2013 06:46 PM | Tags: intermediate basics

Herb Sutter is resuming his Guru of the Week series of problem-and-solution articles about coding in C++, with the intent to gradually update the 88 existing issues and write a few more along the way.

The first problem was posted today:

GotW #1: Variable Initialization -- or Is It? (3/10)

by Herb Sutter

This first problem highlights the importance of understanding what you write. Here we have a few simple lines of code — most of which mean something different from all the others, even though the syntax varies only slightly.

The solution is coming "soon"...

Quick Q: Why does shared_ptr of void work? -- StackOverflow

By Blog Staff | May 2, 2013 11:16 AM | Tags: intermediate basics

Quick A: When it comes to destruction, only your deleter knows for sure... but he's captured at construction time, so all starts well and stays well.

Why do std::shared_ptr<void> work

I found some code using std::shared_ptr to perform arbitrary cleanup at shutdown. At first I thought this code could not possibly work, but then I tried the following:

[edited]

int main() {
  vector<shared_ptr<void>> v;
  {
    v.push_back( shared_ptr<test>( new test() ) );
  }
} // [[ how can this destroy type-safely? ]]

Quick Q: static constexpr variable vs. constexpr function? -- StackOverflow

By Blog Staff | May 1, 2013 04:39 PM | Tags: intermediate basics

With a nice Quick A by Morwenn that not only gives the right answer as of today, but is current with a feature voted into C++14 just two weeks ago that lets you drop the ()'s:

static constexpr variable vs. function

Is there a difference between declaring floating point constant as a static constexpr variable and a function as in example below, or is it just a matter of style?

class MY_PI
{
public:
    static constexpr float MY_PI_VAR = 3.14f;
    static constexpr float MY_PI_FUN() { return 3.14f; }
}

An Idiot's Guide to C++ Templates -- Ajay Vijayvargiya

By Blog Staff | Apr 30, 2013 06:18 AM | Tags: intermediate

A lot of people appreciated the information in this pair of articles, which cover the noted topics:

An Idiot's Guide to C++ Templates -- Part 1

The Syntax Drama

Function Templates

  • Pointers, References and Arrays with Templates
  • Multiple Types with Function Templates
  • Function Template -- Template Function
  • Explicit Template Argument Specification
  • Default Arguments with Function Templates

Class Templates

  • Multiple Types with Class Templates
  • Non-type Template Arguments
  • Template Class as Argument to Class Template
  • Default Template Arguments with Class Templates
  • Class' Methods as Function Templates

An Idiot's Guide to C++ Templates -- Part 2

Requirements from the Underlying Type

  • Requirements: Function Templates
  • Requirements: Class Templates

Separation of Declaration and Implementation

  • Separating Class Implementation

Templates and Other Aspects of C++

  • Class Templates, Friends
  • Class Templates, Operator Overloading
  • Class Templates, Inheritance
  • Function Pointers and Callbacks
  • Templates and Virtual Functions
  • Templates and Macros
  • Function Overloading

STL - An Introduction

Templates and Library Development

Explicit Instantiation

C++ on the Web: Run Your Big 3D Game in the Browser! -- Andre Weissflog

By Blog Staff | Apr 26, 2013 02:37 PM | Tags: intermediate

cpp-web.PNGBuilding C++ to target Javascript (e.g., asm.js) and execute C++ in the browser is becoming quite the popular indoor sport. Here's a current presentation and experience report:

C++ on the Web: Run your big 3D Game in the browser! (slides)

by Andre Weissflog
Head of Development, Berlin
Bigpoint GmbH

My presentation about porting large C/C++ code bases to the browser (emscripten, flascc, Google Native Client)

From the Wrap-up slide:

  • You can run big C/C++ code bases ("a million lines of code") in the browser.
  • Javascript is already fast enough for many types of games.
  • Massive performance improvements happening right now (better code generation, JS engines better at running generated code, asm.js...)
  • ...

Preconditions, Part 4 -- Andrzej Krzemieński

By Blog Staff | Apr 23, 2013 04:38 AM | Tags: intermediate

Here is Andrzej's final (for now) post on preconditions, posted just 

Preconditions — Part IV

by Andrzej Krzemieński

This is the last post about preconditions. We will try to address concerns about a potential UB connected with expressing preconditions. We will also try to explore how language support for preconditions could look like.

 

...

Such a support for preconditions would be a very helpful feature. But let’s not fantasize too much. For now the best thing we can do is to use assertions and comments -- a very useful and often underestimated language feature.

Universal References (revisited) -- Ben Hekster

By Blog Staff | Apr 8, 2013 03:47 PM | Tags: intermediate

A response to Scott Meyers' recent article on Universal References, showing an analogy between &&-collapsing and const-collapsing, and making the counterargument that inventing a new concept may not be needed to clearly explain the standard. It's always interesting to see different experts' takes on how to understand and teach a  feature, particularly a new C++11 feature that we as a community are still absorbing.

Universal References

by Ben Hekster

... The ‘universal reference’ is not a concept you will see defined in the C++ standard, nor is it even something that has any conceptually objective existence in the language or compilation process. It is a construct defined by Meyers in an attempt to make some sense of behavior in the language that he presents as being unexpected or even mysterious. On closer inspection, however, I find that the observed mysterious behavior is actually quite readily explained and has an existing analog that corresponds to already intuitively-understood behavior. ...

Complex Initialization for a Const Variable -- Herb Sutter

By Blog Staff | Apr 5, 2013 01:55 PM | Tags: intermediate

How do you declare a const int variable when you have still have to do some computation to initialize it (so it shouldn't be const at first) but then want it be const after that?

Complex Initialization for a Const Variable

by Herb Sutter

 

On std-discussion, Shakti Misra asked:

> I have seen in a lot of places code like

int i;
if(someConditionIstrue)
{
    Do some operations and calculate the value of i;
    i = some calculated value;
}
use i; //Note this value is only used not changed. It should not be changed.

 

Olaf nailed it: The way to do it is with a lambda. ...