Difference between revisions of "cpp/container/list/empty"
From cppreference.com
m (1 revision: import content) |
m (langlinks) |
||
| (4 intermediate revisions by one user not shown) | |||
| Line 1: | Line 1: | ||
| − | {{cpp/container/empty|list}} | + | {{include page|cpp/container/empty|list}} |
| + | |||
| + | {{langlinks|de|es|fr|it|ja|pt|ru|zh}} | ||
Latest revision as of 07:45, 13 November 2021
bool empty() const; |
(noexcept since C++11) | |
Checks if the container has no elements, i.e. whether begin() == end().
Contents |
[edit] Parameters
(none)
[edit] Return value
true if the container is empty, false otherwise.
[edit] Complexity
Constant.
[edit] Example
The following code uses empty to check if a std::list<int> contains any elements:
Run this code
#include <list> #include <iostream> int main() { std::list<int> numbers; std::cout << std::boolalpha; std::cout << "Initially, numbers.empty(): " << numbers.empty() << '\n'; numbers.push_back(42); numbers.push_back(13317); std::cout << "After adding elements, numbers.empty(): " << numbers.empty() << '\n'; }
Output:
Initially, numbers.empty(): true After adding elements, numbers.empty(): false
[edit] See also
| returns the number of elements (public member function) | |
| (C++17) |
checks whether the container is empty (function template) |
