Type alias (since C++11)

 

C++

Language

Concepts

Utilities library

Strings library

Containers library

Algorithms library

Iterators library

Numerics library

Input/output library

Localizations library

Regular expressions library (C++11)

Atomic operations library (C++11)

Thread support library (C++11)

 

C++ language

General topics
Preprocessor
Comments
Keywords
ASCII chart
Escape sequences
History of C++
Flow control
Conditional execution statements
if statement	switch statement
Iteration statements
for loop range-for loop (C++11)	while loop do-while loop
Jump statements
continue statement break statement	goto statement return statement
Functions
function declaration
lambda function declaration
function template
inline specifier
exception specifications (deprecated)
noexcept specifier (C++11)
Exceptions
throw expression	try-catch block
Namespaces
namespace declaration	namespace aliases
Types
fundamental types compound types enumeration types	union types function types
decltype specifier (C++11)
Specifiers
cv specifiers
storage duration specifiers
constexpr specifier (C++11)
auto specifier (C++11)
alignas specifier (C++11)
Literals
integer literals character literals floating-point literals string literals	boolean literals nullptr (C++11) user-defined (C++11)
Expressions
value categories order of evaluation	operators operator precedence
alternative representations
Utilities
Types
typedef declaration
type alias declaration (C++11)
attributes (C++11)
Casts
implicit conversions
const_cast conversion
static_cast conversion
dynamic_cast conversion
reinterpret_cast conversion
C-style and functional cast
Memory allocation
new expression	delete expression
Classes
class declaration this pointer access specifiers	friend specifier initializer lists
Class-specific function properties
virtual function override specifier (C++11) final specifier (C++11)	explicit (C++11) static
Special member functions
default constructor copy constructor move constructor (C++11)	copy assignment move assignment (C++11) destructor
Templates
class template
function template
template specialization
parameter packs (C++11)
Miscellaneous
Inline assembly

 

Type aliases are similar to typedefs, however, have the advantage of working with templates.

Syntax

using identifier = type_name;

Examples

using flags = std::ios_base::fmtflags;
using func = void (*) (int,int);
// typedef std::ios_base::fmtflags flags;
// typedef void (*func)(int, int);
 
template<class T> using ptr = T*;
ptr<int> x;
 
template<class T> using vec = std::vector<T>;
vec<float> w;
 
// type alias used to hide some template parameter 
template<class CharT> using mystring = std::basic_string<CharT,std::char_traits<CharT>>;
mystring<char> str;
 
// type alias used to simplify the syntax of std::enable_if
template< class Condition >
using EnableIf = Invoke<std::enable_if<Condition::value>>;
 
template <typename T, typename = EnableIf<std::is_polymorphic<T>>>
int f(T t);