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std::vector<T,Allocator>::size

From cppreference.com
< cpp‎ | container‎ | vector
 
 
Containers library
Sequence
(C++11)
Associative
Unordered associative
Adaptors
Views
(C++20)
 
 
size_type size() const;
(until C++11)
size_type size() const noexcept;
(since C++11)
(until C++20)
constexpr size_type size() const noexcept;
(since C++20)

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

Contents

[edit] Parameters

(none)

[edit] Return value

The number of elements in the container.

[edit] Complexity

Constant.

[edit] Example

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

#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.

[edit] See also

returns the number of elements that can be held in currently allocated storage
(public member function) [edit]
checks whether the container is empty
(public member function) [edit]
returns the maximum possible number of elements
(public member function) [edit]
changes the number of elements stored
(public member function) [edit]