std::array<T,N>::empty
constexpr bool empty() const noexcept; | (since C++11) |
Checks if the container has no elements, i.e., whether begin() == end().
Return value
true if the container is empty, false otherwise.
Complexity
Constant.
Example
The following code uses empty to check if a std::array contains any elements:
#include <array>
#include <iostream>
int main()
{
std::array<int, 4> numbers{3, 1, 4, 1};
std::array<int, 0> no_numbers;
std::cout << std::boolalpha;
std::cout << "numbers.empty(): " << numbers.empty() << '\n';
std::cout << "no_numbers.empty(): " << no_numbers.empty() << '\n';
}
Output:
numbers.empty(): false no_numbers.empty(): true
See also
| returns the number of elements (public member function) |
|
|
(C++17) | checks whether the container is empty (function template) |
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