pair

Utility Class

• Summary
• Data Type and Member Function Indexes
• Synopsis
• Description
• Interface
• Types
• Constructors
• Destructors
• Non-member Operators
• Non-member Functions

A template for heterogeneous pairs of values.

Data Types

first_type second_type

Member Functions
make_pair() operator!=() operator>() operator>=() operator<() operator<=()	operator==()

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

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

template <class T1, class T2>
 struct pair {
        typedef T1 first_type;
        typedef T2 second_type;
        T1 first;
        T2 second;
        pair();
        pair (const T1&, const T2&);
        template <class V, class U>
        pair (const pair <V, U>& p);
        ~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>
 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>
 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&);

first_type

Type of the first element in a pair.

second_type

Type of the second element in a pair.

pair ();

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

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

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

template <class V, class U>
pair (const pair <V, U>& p);

Copies first and second from the corresponding elements of p.

~pair ();

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 !(x==y).

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

Returns y < x.

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

Returns !(y < x).

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

Returns !(x < y).

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.