c++11

What does T&& (double ampersand) mean in C++11?

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I’ve been looking into some of the new features of C++11 and one I’ve noticed is the double ampersand in declaring variables, like T&& var. For a start, what is this beast called? I wish Google would allow us to search for punctuation like this. What exactly does it mean? At first glance, it appears … Read more

push_back vs emplace_back

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I’m a bit confused regarding the difference between push_back and emplace_back. void emplace_back(Type&& _Val); void push_back(const Type& _Val); void push_back(Type&& _Val); As there is a push_back overload taking a rvalue reference I don’t quite see what the purpose of emplace_back becomes? 7 s 7 In addition to what visitor said : The function void emplace_back(Type&& … Read more

What is the difference between ‘typedef’ and ‘using’ in C++11?

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I know that in C++11 we can now use using to write type alias, like typedefs: typedef int MyInt; Is, from what I understand, equivalent to: using MyInt = int; And that new syntax emerged from the effort to have a way to express “template typedef”: template< class T > using MyType = AnotherType< T, … Read more

What are rvalues, lvalues, xvalues, glvalues, and prvalues?

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In C++03, an expression is either an rvalue or an lvalue. In C++11, an expression can be an: rvalue lvalue xvalue glvalue prvalue Two categories have become five categories. What are these new categories of expressions? How do these new categories relate to the existing rvalue and lvalue categories? Are the rvalue and lvalue categories … Read more

Why should I use a pointer rather than the object itself?

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I’m coming from a Java background and have started working with objects in C++. But one thing that occurred to me is that people often use pointers to objects rather than the objects themselves, for example this declaration: Object *myObject = new Object; rather than: Object myObject; Or instead of using a function, let’s say … Read more