tuple_element Class <tuple>

2018-01-02

The latest version of this topic can be found at tuple_element Class.

Wraps a tuple element.

Syntax

// CLASS tuple_element (find element by index)  
template <size_t Index, class Tuple>  
struct tuple_element;  
 
// tuple_element for const 
template <size_t Index, class Tuple>  
struct tuple_element<Index, const Tuple>;  
 
// tuple_element for volatile  
template <size_t Index, class Tuple>  
struct tuple_element<Index, volatile Tuple>;  
 
// tuple_element for const volatile  
template <size_t Index, class Tuple>  
struct tuple_element<Index, const volatile Tuple>;  
 
template <size_t Index, class Tuple>  
using tuple_element_t = typename tuple_element<Index, Tuple>::type;

Parameters

Index
The index of the designated element.

Tuple
The type of the tuple.

Remarks

The template class has a nested typedef type that is a synonym for the type at index Index of the tuple type Tuple.

Example

#include <tuple>  
#include <string>  
#include <iostream>  
  
using namespace std;  
typedef tuple<int, double, string> MyTuple;  
  
int main()  
{  
  
    MyTuple c0{ 0, 1.5, "Tail" };  
  
    tuple_element_t<0, MyTuple> val = get<0>(c0); //get by index  
    tuple_element_t<1, MyTuple> val2 = get<1>(c0);  
    tuple_element_t<2, MyTuple> val3 = get<string>(c0); // get by type  
  
    cout << val << " " << val2 << " " << val3 << endl;  
}  
  
/*  
Output:  
0 1.5 Tail  
*/

Requirements

Header: <tuple>

Namespace: std

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