std::multiset<Key,Compare,Allocator>::empty
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::multiset<int> contains any elements:
#include <iostream>
#include <set>
int main()
{
std::multiset<int> numbers;
std::cout << std::boolalpha;
std::cout << "Initially, numbers.empty(): " << numbers.empty() << '\n';
numbers.insert(42);
numbers.insert(19937);
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) |
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