is_same Class
The latest version of this topic can be found at is_same Class.
Tests if two types are the same.
Syntax
template <class Ty1, class Ty2>
struct is_same;
Parameters
Ty1
The first type to query.
Ty2
The second type to query.
Remarks
An instance of the type predicate holds true if the types Ty1 and Ty2 are the same type, otherwise it holds false.
Example
// std_tr1__type_traits__is_same.cpp
// compile with: /EHsc
#include <type_traits>
#include <iostream>
struct base
{
int val;
};
struct derived
: public base
{
};
int main()
{
std::cout << "is_same<base, base> == " << std::boolalpha
<< std::is_same<base, base>::value << std::endl;
std::cout << "is_same<base, derived> == " << std::boolalpha
<< std::is_same<base, derived>::value << std::endl;
std::cout << "is_same<derived, base> == " << std::boolalpha
<< std::is_same<derived, base>::value << std::endl;
std::cout << "is_same<int, int> == " << std::boolalpha
<< std::is_same<int, int>::value << std::endl;
std::cout << "is_same<int, const int> == " << std::boolalpha
<< std::is_same<int, const int>::value << std::endl;
return (0);
}
is_same<base, base> == true
is_same<base, derived> == false
is_same<derived, base> == false
is_same<int, int> == true
is_same<int, const int> == false
Requirements
Header: <type_traits>
Namespace: std