NAME

std::set::size - std::set::size

Synopsis

size_type size() const; (until C++11)
size_type size() const noexcept; (since C++11)

Returns the number of elements in the container, i.e. std::distance(begin(), end()).

Parameters

(none)

Return value

The number of elements in the container.

Complexity

Constant.

Example

The following code uses size to display the number of elements in a std::set<int>:

// Run this code

#include <set>
#include <iostream>

int main()
{
std::set<int> nums {1, 3, 5, 7};

std::cout << "nums contains " << nums.size() << " elements.\n";
}

Output:

nums contains 4 elements.

See also

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