Explore the full potential of C++ by mastering the standard library.

Become a C++ Programmer

The C++ standard library is a collection of all the tools and utilities available in C++. It received its latest update in 2017, known as C++17. The update introduces many new features that further optimize our code. This module will help us fully grasp C++ and use it to its full potential.

C++ Standard Library

A reference wrapper is a [copy-constructible](http://en.cppreference.com/w/cpp/concept/CopyConstructible) and [copy-assignable](http://en.cppreference.com/w/cpp/concept/CopyAssignable) wrapper for a object of type&, which is defined in the header `<functional>`. So you have an object, that behaves like a reference, but can be copied. Contrary to classic references, [`std::reference_wrapper`](http://en.cppreference.com/w/cpp/utility/functional/reference_wrapper) objects support two additional use cases:

* You can use them in containers of the Standard Template Library. `std::vector<std::reference_wrapper<int>> myIntRefVector`
* You can copy instances of classes, which have `std::reference_wrapper` objects. That is in general not possible with references.

To access the reference of a  `std::reference_wrapper<int> myInt(1)`, the get method can be used: `myInt.get()`. You can use a reference wrapper to encapsulate and invoke a callable.

C++ takes reference functionality one step higher by introducing reference wrappers!

Introduction