Difference between revisions of "cpp/container/list/empty"
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Revision as of 07:25, 14 October 2012
bool empty() const; |
(noexcept since C++11) | |
Checks if the container has no elements, i.e. whether begin() == end().
Contents |
Parameters
(none)
Return value
true if the container is empty, false otherwise.
Complexity
Constant.
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
See also
| returns the number of elements (public member function) | |
| (C++17) |
checks whether the container is empty (function template) |
