pair(); pair( const T1 &a, const T2 &b );
The pair struct is a way to store two pieces of heterogeneous data.
These data may be accessed using the
second fields of a pair.
Pairs may be tested for equality with the
== operator. The
< operator is also defined for pairs; given two pairs
< operator returns:
x.first < y.first || ((y.first == x.first) && x.second < y.second)
The make_pair function can be used as a shortcut when creating pairs to avoid explicitly specifying the types for the two pieces of data.