std::array::empty

 

C++

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constexpr bool empty();		(since C++11)

Checks if the container has no elements, i.e. whether begin() == end().

Parameters

(none)

Return value

true if the container is empty, false otherwise

Exceptions

noexcept specification:  

noexcept

  (since C++11)

Complexity

Constant

Example

The following code uses empty to check if a std::array<int> contains any elements:

run this code

#include <array>
#include <iostream>
 
int main()
{
    std::array<int, 4> numbers {3, 1, 4, 1};
    std::array<int, 0> no_numbers;
 
    std::cout << "numbers.empty(): " << numbers.empty() << '\n';
    std::cout << "no_numbers.empty(): " << no_numbers.empty() << '\n';
}

Output:

numbers.empty(): 0
no_numbers.empty(): 1

See also

size	returns the number of elements (public member function)