The C++ Standard Library Extensions A Tutorial and Reference

Chapter 1. Tuples

You cannot conceive of the many without the one.

— ParmenidesPLATO

The class template tuple is a generalization of the standard C++ library class template pair. The pair template takes two type arguments; objects of type pair<T₁, T₂> hold two elements: one of type T₁ and one of type T₂. The tuple template extends this by taking an arbitrary number of type arguments. Objects of type tuple<T₁, T₂, …, T_N> hold N elements of types T₁, T₂, …, T_N, respectively.^[1]

Example 1.1. Tuple Declarations (tuples/typedefs.cpp)

#include <tuple>using std::tr1::tuple;tuple<> none;                      // holds no elementstuple<int> one;                    // holds one element, of type intint i; double d;tuple<int&, const double&>    two(i, d);                      //  ...