unordered_multimap hash_function() in C++ STL
The unordered_multimap::hash_function() is a built-in function in C++ STL which is used to get the hash function. This hash function is a unary function which takes a single argument only and returns a unique value of type size_t based on it.
Syntax:
unordered_multimap_name.hash_function()
Parameter: The function does not accept any parameter.
Return Value: The function returns the hash function.
Below programs illustrate the unordered_multimap::hash_function() function:
Program 1:
// C++ program to illustrate the // unordered_multimap::hash_function() #include <iostream> #include <unordered_map> using namespace std; int main() { // declaration unordered_multimap<string, string> sample; // inserts key and elements sample.insert({ "gopal" , "dave" }); sample.insert({ "gopal" , "dave" }); sample.insert({ "gopal" , "dave" }); sample.insert({ "Beginner" , "Beginner" }); // use of hash_function unordered_multimap<string, string>::hasher fn = sample.hash_function(); cout << fn( "Beginner" ) << endl; // print the key and elements cout << "Key and Elements: " ; for ( auto it = sample.begin(); it != sample.end(); it++) { cout << "{" << it->first << ":" << it->second << "}, " ; } return 0; } |
Output:
15276750567035005396 Key and Elements: {Beginner:Beginner}, {gopal:dave}, {gopal:dave}, {gopal:dave},
Program 2:
// C++ program to illustrate the // unordered_multimap::hash_function() #include <iostream> #include <unordered_map> using namespace std; int main() { // declaration unordered_multimap<string, string> sample; // insertion of key and elements sample.insert({ "gopal" , "dave" }); sample.insert({ "Beginner" , "Beginner" }); // use of hash_function unordered_multimap<string, string>::hasher fn = sample.hash_function(); cout << fn( "w3wiki" ) << endl; // print the key and elements cout << "Key and Elements: " ; for ( auto it = sample.begin(); it != sample.end(); it++) { cout << "{" << it->first << ":" << it->second << "}, " ; } return 0; } |
Output:
5146686323530302118 Key and Elements: {Beginner:Beginner}, {gopal:dave},
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