C++ Utility std::pair template

The C++ std::pair templates consist of only two data members.And these two objects are treated as a pair.The types of the objects can be same or different.The std::pair template is defined under <utility> header.

templates declaration

namespace std {
template<typename T1, typename T2>
struct pair;
}

Data members

Note::They belong to public type.

Constructors and copy-constructor

Note:they are all templates.

Member functions

Non-member functions

There is also another ‘swap‘ function that accept various types of data,not just pair objects.

 #include <iostream>
#include <utility>
using namespace std ;

int main( )
{
pair<int , string> pr{ 45 , “Pair string” } ,
pr1={23 , “New pair string”}; ///work fine

cout<< pr.first << endl ///gives the first data 
<< pr.second ; ///gives the second data

pair<int , string> pr1{ 46 , “Pair string” };

cout<< (pr!=pr1) ; //give true

pair<double, string> prDs={ “23.45” , “1290” } ; ///error,type does not match

cin.get( );
return 0 ;
}

Output

45
Pair string
1