| (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: noexceptComplexity
Constant.
Example
The following code uses empty to check if a std::unordered_multiset<int> contains any elements:
1 2 3 4 5 6 7 8 9 10 11 12 | #include <unordered_set>#include <iostream> int main(){ std::unordered_multiset<int> numbers; std::cout << "Initially, numbers.empty(): " << numbers.empty() << '\n'; numbers.insert(42); numbers.insert(13317); std::cout << "After adding elements, numbers.empty(): " << numbers.empty() << '\n';} |
Output:
1 2 | Initially, numbers.empty(): 1After adding elements, numbers.empty(): 0 |
See also
| returns the number of elements (public member function) |
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