map::swap
Exchanges the elements of two maps.
void swap(
map<Key, Type, Traits, Allocator>& _Right
);
Parameters
- _Right
The argument map providing the elements to be swapped with the target map.
Remarks
The member function invalidates no references, pointers, or iterators that designate elements in the two maps whose elements are being exchanged.
Example
// map_swap.cpp
// compile with: /EHsc
#include <map>
#include <iostream>
int main( )
{
using namespace std;
map <int, int> m1, m2, m3;
map <int, int>::iterator m1_Iter;
typedef pair <int, int> Int_Pair;
m1.insert ( Int_Pair ( 1, 10 ) );
m1.insert ( Int_Pair ( 2, 20 ) );
m1.insert ( Int_Pair ( 3, 30 ) );
m2.insert ( Int_Pair ( 10, 100 ) );
m2.insert ( Int_Pair ( 20, 200 ) );
m3.insert ( Int_Pair ( 30, 300 ) );
cout << "The original map m1 is:";
for ( m1_Iter = m1.begin( ); m1_Iter != m1.end( ); m1_Iter++ )
cout << " " << m1_Iter -> second;
cout << "." << endl;
// This is the member function version of swap
//m2 is said to be the argument map; m1 the target map
m1.swap( m2 );
cout << "After swapping with m2, map m1 is:";
for ( m1_Iter = m1.begin( ); m1_Iter != m1.end( ); m1_Iter++ )
cout << " " << m1_Iter -> second;
cout << "." << endl;
// This is the specialized template version of swap
swap( m1, m3 );
cout << "After swapping with m3, map m1 is:";
for ( m1_Iter = m1.begin( ); m1_Iter != m1.end( ); m1_Iter++ )
cout << " " << m1_Iter -> second;
cout << "." << endl;
}
The original map m1 is: 10 20 30. After swapping with m2, map m1 is: 100 200. After swapping with m3, map m1 is: 300.
Requirements
Header: <map>
Namespace: std