std::flat_multimap<Key,T,Compare,KeyContainer,MappedContainer>::size

 

C++

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External libraries

 

Containers library

Sequence

array (C++11)

vector

vector<bool>

inplace_vector (C++26)

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list

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map

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Unordered associative

unordered_set (C++11)

unordered_multiset (C++11)

unordered_map (C++11)

unordered_multimap (C++11)

Adaptors

stack

queue

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flat_set (C++23)

flat_multiset (C++23)

flat_map (C++23)

flat_multimap (C++23)

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span (C++20)

mdspan (C++23)

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std::flat_multimap

Member types

Member functions

flat_multimap::flat_multimap    flat_multimap::operator= Modifiers flat_multimap::clear flat_multimap::erase flat_multimap::swap flat_multimap::extract flat_multimap::replace flat_multimap::insert flat_multimap::insert_range flat_multimap::emplace flat_multimap::emplace_hint Lookup flat_multimap::count flat_multimap::find flat_multimap::contains flat_multimap::equal_range flat_multimap::lower_bound flat_multimap::upper_bound Iterators flat_multimap::beginflat_multimap::cbegin flat_multimap::endflat_multimap::cend flat_multimap::rbeginflat_multimap::crbegin flat_multimap::rendflat_multimap::crend Capacity flat_multimap::size flat_multimap::max_size flat_multimap::empty Observers flat_multimap::key_comp flat_multimap::keys flat_multimap::value_comp flat_multimap::values

Non-member functions

swap(std::flat_multimap) (C++23) erase_if(std::flat_multimap) (C++23)    operator==operator<=> (C++23)(C++23)

Helper classes

uses_allocator<std::flat_multimap> (C++23)

Tags

sorted_equivalent (C++23)         sorted_equivalent_t (C++23)

Deduction guides

 

size_type size() const noexcept;		(since C++23)

Returns the number of elements in the container adaptor. Equivalent to return c.keys.size().

Parameters

(none)

Return value

The number of elements in the container adaptor.

Complexity

Constant.

Example

The following code uses size to display the number of elements in a std::flat_multimap:

Run this code

#include <iostream>
#include <flat_map>
 
int main()
{
    std::flat_multimap<int,char> nums{{1, 'a'}, {3, 'b'}, {5, 'c'}, {7, 'd'}};
 
    std::cout << "nums contains " << nums.size() << " elements.\n";
}

Output:

nums contains 4 elements.

See also

empty	checks whether the container adaptor is empty (public member function)
sizessize (C++17)(C++20)	returns the size of a container or array (function template)
max_size	returns the maximum possible number of elements (public member function)