unordered_multimap::swap

Article
12/01/2015

Swaps the contents of two containers.

Syntax

void swap(unordered_multimap& right);

Parameters

right
The container to swap with.

Remarks

The member function swaps the controlled sequences between *this and right. If unordered_multimap::get_allocator() == right.get_allocator(), it does so in constant time, it throws an exception only as a result of copying the stored traits object of type Tr, and it invalidates no references, pointers, or iterators that designate elements in the two controlled sequences. Otherwise, it performs a number of element assignments and constructor calls proportional to the number of elements in the two controlled sequences.

Example

// std_tr1__unordered_map__unordered_multimap_swap.cpp 
// compile with: /EHsc 
#include <unordered_map> 
#include <iostream> 

typedef std::unordered_multimap<char, int> Mymap; 
int main() 
    { 
    Mymap c1; 

    c1.insert(Mymap::value_type('a', 1)); 
    c1.insert(Mymap::value_type('b', 2)); 
    c1.insert(Mymap::value_type('c', 3)); 

// display contents " [c 3] [b 2] [a 1]" 
    for (Mymap::const_iterator it = c1.begin(); 
        it != c1.end(); ++it) 
        std::cout << " [" << it->first << ", " << it->second << "]"; 
    std::cout << std::endl; 

    Mymap c2; 

    c2.insert(Mymap::value_type('d', 4)); 
    c2.insert(Mymap::value_type('e', 5)); 
    c2.insert(Mymap::value_type('f', 6)); 

    c1.swap(c2); 

// display contents " [f 6] [e 5] [d 4]" 
    for (Mymap::const_iterator it = c1.begin(); 
        it != c1.end(); ++it) 
        std::cout << " [" << it->first << ", " << it->second << "]"; 
    std::cout << std::endl; 

    swap(c1, c2); 

// display contents " [c 3] [b 2] [a 1]" 
    for (Mymap::const_iterator it = c1.begin(); 
        it != c1.end(); ++it) 
        std::cout << " [" << it->first << ", " << it->second << "]"; 
    std::cout << std::endl; 

    return (0); 
    }

[c, 3] [b, 2] [a, 1]
[f, 6] [e, 5] [d, 4]
[c, 3] [b, 2] [a, 1]

Requirements

Header: <unordered_map>

Namespace: std