C++11 - Uniform initialization

C++11 standard provides new form of objects initialization which makes such initialization uniform for different structs and classes and simplify objects construction and initialization process. Thanks to the new process we can initialize many different classes using the same syntax.

Please take a look on the example below: Output of this example is: In point I we are initializing class of two different objects using C++11 uniform initialization mechanism. On object is created based on struct type (pure struct type without any method - look point II). The second one is created based on MyClass class constructor.

As you can see, despite that we are creating objects of two totally different types, those objects can be created the same way (uniform way). This is just uniform unitialization featuere provided in C++11 standard.

Below we are initializating MyStruct object using external function getMyStruct(). You can take a look to the body of that function (point IV). As you can see we are implicitly using uniform initialization form of struct MyStruct inside getMyStruct() function to create object.

However you need to be careful with using uniform initialization for classes having initializer_list constructor. In such case, initializer list constructor has higher priority than uniform initialization and constructor will be used instead of uniform initialization. So be aware of it and enjoy your C++11 programming :)

Code of this article's example you can find on our GitHub account here: https://github.com/xmementoit/CppAdventureExamples/tree/master/cpp11/uniformInitialization

Comments

Blog's new layout

As you noticed this blog has new layout from today. I hope you like it. I think new layout looks better and more modern than previous one. Please, write you opinion about new layout in comments. If you have some ideas how to make this blog better, all ideas are welcomed. Enjoy new layout and blog articles.

STL - count and count_if algorithms

One of the basic and most useful STL algorithms is algorithm which can be used to count number of elements within selected container according to specified criteria. In order to do that we can use std::count or std::count_if algorithm. std::count (firstElementIterator, lastElementIterator, elementForSearch) - is function which will go through container using firstElementIterator and lastElementIterator and return number of container elements which value is equal elementForSearch std::count_if (firstElementIterator, lastElementIterator, UnaryPredicateFunction) - is function which examine range from firstElementIterator to lastElementIterator and return number of container elements which fulfill UnaryPredicateFunction criteria. UnaryPredicateFunction is function having following signature: bool functionName(const Type& a) . So, count_if returns number of elements where UnaryPredicateFunction returns true for. For better understanding let's take a...

QT - foreach algoriithm with const references performance improvement

Today I would like to show you optimal way of using foreach QT algorithm . I will show you why we should pass elements of foreach algorithm by const reference instead of passing them by value. Let me explain it on the below example: Output of this example is: In point I we are creating 3 objects of MyClass class and push them to myClasses QList element. In point II we are using QT foreach algorithm to invoke getValue() method for each object from myClasses list. As you can see on output text for that part of code we are invoking copy constructor before and destructor after invoking getValue() function. It is because we are passing each myClasses list element to foreach algorithm by value. Therefore we are copying that element at the beginning of foreach loop step and removing them (destructing) at the end. This is inefficient solution, especially when class of object being copied is big. It decreases performance. of our application. Solution for that i...

Developer Adventure

Search This Blog