std::vector::size

 

C++

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Technical Specifications

 

Containers library

array (C++11)

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std::vector

Member functions

vector::vector

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Element access

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vector::beginvector::cbegin (C++11)

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Capacity

vector::empty

vector::size

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vector::capacity

vector::shrink_to_fit (C++11)

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size_type size() const;

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.

Exceptions

(none)	(until C++11)
noexcept specification:   noexcept	(since C++11)

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

capacity	returns the number of elements that can be held in currently allocated 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)