std::unordered_multimap::empty
From cppreference.com
< cpp | container | unordered multimap
| bool empty() const; |
(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] Exceptions
noexcept specification:
noexcept
[edit] Complexity
Constant.
[edit] Example
The following code uses empty to check if a std::unordered_multimap<int,int> contains any elements:
Run this code
#include <unordered_map> #include <iostream> #include <utility> int main() { std::unordered_multimap<int, int> numbers; std::cout << "Initially, numbers.empty(): " << numbers.empty() << '\n'; numbers.emplace(42, 13); numbers.insert(std::make_pair(13317, 123)); std::cout << "After adding elements, numbers.empty(): " << numbers.empty() << '\n'; }
Output:
Initially, numbers.empty(): 1 After adding elements, numbers.empty(): 0
See also
| returns the number of elements (public member function) |
