unordered_map bucket() in C++ STL

The unordered_map::bucket() is a built-in STL function in C++ which returns the bucket number where the element with the key k is located in the map. 
Syntax: 
 

size_type bucket(key) 

Parameter: The function accepts one mandatory parameter key which specifies the key whose bucket number is to be returned. 
Return Value: This method returns an unsigned integral type which represents the bucket number of the key k which is passed in the parameter. 
Below program illustrate the unordered_map::bucket() function: 
 

The bucket number of key France is 3