is_rvalue_reference Template in C++
The std::is_rvalue_reference template of C++ STL is used to check whether the type is a rvalue reference type or not. It returns a boolean value showing the same.
Syntax:
template <class T > struct is_rvalue_reference;
Parameters: This template accepts a single parameter T (Trait class) to check whether T is a rvalue reference type.
Return Value: This template returns a boolean value as shown below:
- True: if the type is a rvalue_reference type.
- False: if the type is a non-rvalue_reference type.
Below programs illustrate the std::is_lvalue_reference template in C++ STL:
Program 1:
// C++ program to illustrate // std::is_rvalue_reference template #include <iostream> #include <type_traits> using namespace std; // main program class gfg { }; int main() { cout << std::boolalpha; cout << "is_rvalue_reference: " << '\n' ; cout << "gfg: " << is_rvalue_reference<gfg>::value << '\n' ; cout << "gfg&: " << is_rvalue_reference<gfg&>::value << '\n' ; cout << "gfg&&: " << is_rvalue_reference<gfg&&>::value << '\n' ; return 0; } |
Output:
is_rvalue_reference: gfg: false gfg&: false gfg&&: true
Program 2:
// C++ program to illustrate // std::is_rvalue_reference template #include <iostream> #include <type_traits> using namespace std; // main program int main() { cout << std::boolalpha; cout << "is_rvalue_reference: " << '\n' ; cout << "int: " << is_rvalue_reference< int >::value << '\n' ; cout << "int&: " << is_rvalue_reference< int &>::value << '\n' ; cout << "int&&: " << is_rvalue_reference< int &&>::value << '\n' ; cout << "char: " << is_rvalue_reference< char >::value << '\n' ; cout << "char&: " << is_rvalue_reference< char &>::value << '\n' ; cout << "char&&: " << is_rvalue_reference< char &&>::value << '\n' ; return 0; } |
Output:
is_rvalue_reference: int: false int&: false int&&: true char: false char&: false char&&: true
Program 3:
// C++ program to illustrate // std::is_rvalue_reference template #include <iostream> #include <type_traits> using namespace std; // main program int main() { cout << std::boolalpha; cout << "is_rvalue_reference: " << '\n' ; cout << "float: " << is_rvalue_reference< float >::value << '\n' ; cout << "float&: " << is_rvalue_reference< float &>::value << '\n' ; cout << "float&&: " << is_rvalue_reference< float &&>::value << '\n' ; cout << "double: " << is_rvalue_reference< double >::value << '\n' ; cout << "double&: " << is_rvalue_reference< double &>::value << '\n' ; cout << "double&&: " << is_rvalue_reference< double &&>::value << '\n' ; return 0; } |
Output:
is_rvalue_reference: float: false float&: false float&&: true double: false double&: false double&&: true
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