New Meanings of the old keywords in C ++ 11 (auto, using, extern)

C ++ 11 revised the keywords and added nullptr, constexpr, decltype, default, static_assert, and the original keywords (auto, using, extern) the meaning and purpose were revised. Here we will take a look at the revision of the three keywords auto, using, and extern.

Auto

Automated Variables

Auto a = 12;

Auto B = 12.0f;

Auto c = true;

Auto d = [] (int x)-> int {return 12 ;};

Auto e = std: bind (& func, _ 1 );

Delayed binding

Template <typename T, typename L>

Auto fun (T x, L y)-> decltype (x + y) {return x ;}

Using

Define aliases

Template <typename T>

Using Tlist = std: list <T>;

Using df = void (*) (); (equivalent to typedef void (* df )())

Use external structures

Using A:;

Extern

External Template

Extern template <typename T> void (T t ){}