tuple_size Class <utility>
The latest version of this topic can be found at Visual Studio 2017 Documentation.
Wraps pair element count.
Syntax
template <class Tuple>
struct tuple_size;
template <class T1, class T2>
struct tuple_size<pair<T1, T2>> : integral_constant<size_t, 2>
// size of const tuple
template <class Tuple>
struct tuple_size<const Tuple>;
// size of volatile tuple
template <class Tuple>
struct tuple_size<volatile Tuple>;
// size of const volatile tuple
template <class Tuple>
struct tuple_size<const volatile Tuple>;
Parameters
T1
The type of the first pair element.
T2
The type of the second pair element.
Remarks
The template is a specialization of the template class tuple_size Class. It has a member value that is an integral constant expression whose value is 2.
Example
#include <utility>
#include <iostream>
using namespace std;
typedef pair<int, double> MyPair;
int main()
{
MyPair c0(0, 1.1);
// display contents " 0 1.1"
cout << " " << get<0>(c0);
cout << " " << get<1>(c0) << endl;
// display size " 2"
cout << " " << tuple_size<MyPair>::value << endl;
}
/*
Output:
0 1.1
2
*/
Requirements
Header: <utility>
Namespace: std