std::multimap::erase

 

C++

Language

Standard library headers

Concepts

Utilities library

Strings library

Containers library

Algorithms library

Iterators library

Numerics library

Input/output library

Localizations library

Regular expressions library (C++11)

Atomic operations library (C++11)

Thread support library (C++11)

Technical Specifications

 

Containers library

array (C++11)

vector

deque

forward_list (C++11)

list

set

multiset

map

multimap

unordered_set (C++11)

unordered_multiset (C++11)

unordered_map (C++11)

unordered_multimap (C++11)

stack

queue

priority_queue

 

std::multimap

Member functions

multimap::multimap

multimap::~multimap

multimap::operator=

multimap::get_allocator

Iterators

multimap::beginmultimap::cbegin (C++11)

multimap::endmultimap::cend (C++11)

multimap::rbeginmultimap::crbegin (C++11)

multimap::rendmultimap::crend (C++11)

Capacity

multimap::erase

multimap::size

multimap::max_size

Modifiers

multimap::clear

multimap::insert

multimap::emplace (C++11)

multimap::emplace_hint (C++11)

multimap::erase

multimap::swap

Lookup

multimap::count

multimap::find

multimap::equal_range

multimap::lower_bound

multimap::upper_bound

Observers

multimap::key_comp

multimap::value_comp

 

	(1)
void erase( iterator pos );			(until C++11)
iterator erase( iterator pos );			(since C++17)
iterator erase( const_iterator pos );			(since C++11)
		(2)
void erase( iterator first, iterator last );				(until C++11)
iterator erase( const_iterator first, const_iterator last );				(since C++11)
size_type erase( const key_type& key );			(3)

Removes specified elements from the container.

1) Removes the element at pos.

2) Removes the elements in the range [first; last), which must be a valid range in *this.

3) Removes all elements with the key equivalent to key.

References and iterators to the erased elements are invalidated. Other references and iterators are not affected.

The iterator pos must be valid and dereferenceable. Thus the end() iterator (which is valid, but is not dereferencable) cannot be used as a value for pos.

Parameters

pos	-	iterator to the element to remove
first, last	-	range of elements to remove
key	-	key value of the elements to remove

Return value

1-2) Iterator following the last removed element.

3) Number of elements removed.

Exceptions

1,2) (none)

3) Any exceptions thrown by the Compare object.

Complexity

Given an instance c of multimap:

1) Amortized constant

2) log(c.size()) + std::distance(first, last)

3) log(c.size()) + c.count(k)

Example

Run this code

#include <map>
#include <iostream>
int main()
{
    std::multimap<int, std::string> c = {{1, "one"}, {2, "two"}, {3, "three"},
                                    {4, "four"}, {5, "five"}, {6, "six"}};
    // erase all odd numbers from c
    for(auto it = c.begin(); it != c.end(); )
        if(it->first % 2 == 1)
            it = c.erase(it);
        else
            ++it;
    for(auto& p : c)
        std::cout << p.second << ' ';
}

Output:

two four six

See also

clear

clears the contents (public member function)