C++ - Unordered Multimap empty() Function
The C++ unordered_multimap::empty function is used to check whether the unordered_multimap is empty or not. It returns true if the size of the unordered_multimap is zero, else returns false.
Syntax
bool empty() const noexcept;
Parameters
No parameter is required.
Return Value
true if the size of the unordered_multimap is zero, else returns false.
Time Complexity
Constant i.e, Θ(1).
Example:
In the below example, the unordered_multimap::empty function is used to check whether the unordered_multimap is empty or not.
#include <iostream> #include <unordered_map> using namespace std; int main (){ unordered_multimap<string, string> uMMap; cout<<"Is the Unordered Multimap empty?: "<<uMMap.empty()<<"\n\n"; cout<<"Add three key/element pairs in the Unordered Multimap:\n"; uMMap.insert(pair<string, string>("USA", "New York")); uMMap.insert(pair<string, string>("USA", "Washington")); uMMap.insert(pair<string, string>("CAN", "Toronto")); cout<<"Now, Is the Unordered Multimap empty?: "<<uMMap.empty()<<"\n"; return 0; }
The output of the above code will be:
Is the Unordered Multimap empty?: 1 Add three key/element pairs in the Unordered Multimap: Now, Is the Unordered Multimap empty?: 0
❮ C++ - Unordered Multimap