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std::flat_map<Key,T,Compare,KeyContainer,MappedContainer>::size - cppreference.com

From cppreference.com

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

#include <cassert>
#include <flat_map>
 
int main()
{
    std::flat_map<int, char> nums{{1, 'a'}, {1, 'b'}, {2, 'c'}, {2, 'd'}};
    assert(nums.size() == 2); 
}

See also

checks whether the container adaptor is empty
(public member function) [edit]
returns the size of a container or array
(function template) [edit]
returns the maximum possible number of elements
(public member function) [edit]