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:
#include <iostream>
#include <unordered_map>
using namespace std;
int main()
{
unordered_multimap<string, string> sample;
sample.insert({ "gopal" , "dave" });
sample.insert({ "gopal" , "dave" });
sample.insert({ "gopal" , "dave" });
sample.insert({ "geeks" , "geeks" });
unordered_multimap<string, string>::hasher fn
= sample.hash_function();
cout << fn( "geeks" ) << endl;
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: {geeks:geeks}, {gopal:dave}, {gopal:dave}, {gopal:dave},
Program 2:
#include <iostream>
#include <unordered_map>
using namespace std;
int main()
{
unordered_multimap<string, string> sample;
sample.insert({ "gopal" , "dave" });
sample.insert({ "geeks" , "geeks" });
unordered_multimap<string, string>::hasher fn
= sample.hash_function();
cout << fn( "geeksforgeeks" ) << endl;
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: {geeks:geeks}, {gopal:dave},
Last Updated :
08 Aug, 2018
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