Usage In a template declaration, typename can be used as an alternative to class to declare type template parameters and template template parameters (since C++17). Inside a declaration or a definition of a template, typename can be used to declare that a dependent name is a type.

This header is part of the type support library. Classes type_info contains some type's information, generated by the implementation. This is the class returned by the typeid operator. (class) bad_typeid exception that is thrown if an argument in a typeid expression is null (class) bad_cast exception that is thrown by an invalid dynamic_cast expression, i.e. a cast of reference type fails (class) Synopsis namespace std { class type_info; class bad_cast; clas

This header is part of the types support library. Classes type_index (C++11) wrapper around a type_info object, that can be used as index in associative and unordered associative containers (class) std::hash<std::type_index> (C++11) hash support for std::type_index (class template specialization) Forward declarations Defined in header <functional> hash (C++11) hash function object (class template) Synopsis namespace std { class type_index;

Queries information of a type. Used where the dynamic type of a polymorphic object must be known and for static type identification. Syntax typeid( type ) (1) typeid( expression ) (2) The header <typeinfo> must be included before using typeid (if the header is not included, every use of the keyword typeid makes the program ill-formed.). The typeid expression is lvalue expression which refers to an object with static storage duration, of the polymorphic type const std::typ

Usage typeid operator

The typedef declaration provides a way to create an alias that can be used anywhere in place of a (possibly complex) type name. Syntax typedef type_declaration; Explanation The declaration that follows the keyword typedef is otherwise usual simple declaration (except that other type specifiers, e.g. static, cannot be used). It may declare one or many identifiers on the same line (e.g. int and a pointer to int), it may declare array and function types, pointers and references, clas

Usage typedef declaration

(See also type for type system overview). Basic types Fundamental types defined by the language Additional basic types and macros Defined in header <cstddef> size_t unsigned integer type returned by the sizeof operator (typedef) ptrdiff_t signed integer type returned when subtracting two pointers (typedef) nullptr_t (C++11) the type of the null pointer literal nullptr (typedef) NULL implementation-defined null pointer constant (macro constant) max_ali

Type alias is a name that refers to a previously defined type (similar to typedef). Alias template is a name that refers to a family of types. Syntax Alias declarations are declarations with the following syntax. using identifier attr(optional) = type-id ; (1) template < template-parameter-list > using identifier attr(optional) = type-id ; (2) attr(C++11) - optional sequence of any number of attributes identifier - the name that is introduced by this declaratio

Objects, references, functions including function template specializations, and expressions have a property called type, which both restricts the operations that are permitted for those entities and provides semantic meaning to the otherwise generic sequences of bits. Type classification The C++ type system consists of the following types: fundamental types (see also std::is_fundamental): the type void (see also std::is_void); the type std::nullptr_t (see also std::is_null_pointer); a