pair

     Utility Class

A template for heterogenous pairs of values.

Contents

• Synopsis
• Description
• Interface
• Constructors and Destructors
• Non-member Operators
• Non-member Functions

#include <utility>
template <class T1, class T2>
struct pair ;

The pair class provides a template for encapsulating pairs of values that may be of different types.

template <class T1, class T2>

 struct pair {
        T1 first;
        T2 second;
        pair();
        pair (const T1&, const T2&);
        ~pair();
};
template <class T1, class T2>
 bool operator== (const pair<T1, T2>&,
                  const pair T1, T2>&);
template <class T1, class T2>
 bool operator< (const pair<T1, T2>&,
                 const pair T1, T2>&);
template <class T1, class T2>
 pair<T1,T2> make_pair (const T1&, const T2&);

pair ();

Default contructor. Initializes first and second using their default constructors.

pair (const T1& x, const T2& y);

The constructor creates a pair of types T1 and T2, making the necessary conversions in x and y.

~pair ();

Destructor.

template <class T1, class T2>
bool operator== (const pair<T1, T2>& x,
                  const pair T1, T2>& y);

Returns true if (x.first == y.first && x.second == y.second) is true. Otherwise it returns false.

template <class T1, class T2>
bool operator< (const pair<T1, T2>& x,
                const pair T1, T2>& y);

Returns true if (x.first < y.first || (!(y.first < x.first) && x.second < y.second)) is true. Otherwise it returns false.

template <class T1, class T2>
pair<T1,T2>
make_pair(x,y);

make_pair(x,y) creates a pair by deducing and returning the types of x and y.