NAME¶

std::vector::size - std::vector::size

Synopsis¶

size_type size() const; (noexcept since C++11)
(constexpr since C++20)

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::vector<int>:

// Run this code

#include <vector>
#include <iostream>

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

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

Output:¶

nums contains 4 elements.

See also¶

returns the number of elements that can be held in currently allocated
capacity storage
(public member function)
empty checks whether the container is empty
(public member function)
max_size returns the maximum possible number of elements
(public member function)
resize changes the number of elements stored
(public member function)
size
ssize returns the size of a container or array
(C++17) (function template)
(C++20)