hash string C++

#include <bitset> 
  
// functional header 
// for hash<class template> class 
#include <functional> 
  
#include <iostream> 
#include <string> 
#include <vector> 
  
using namespace std; 
  
// To demonstrate String Hashing 
void stringHashing() 
{ 
  
    // Get the string 
    // to get its hash value 
    string hashing1 = "Geeks"; 
  
    // Instatiation of Object 
    hash<string> mystdhash; 
  
    // Using operator() to get hash value 
    cout << "String hash values: "
         << mystdhash(hashing1) 
         << endl; 
} 
  
// To demonstrate BITSET Hashing 
void bitsetHashing() 
{ 
  
    // Get the BITSET 
    // to get its hash value 
    bitset<5> h_bitset("10101"); 
  
    // Instatiation of Object 
    hash<bitset<5> > hash_bitset; 
  
    // Using operator() to get hash value 
    cout << "\nBitset 10101 hash value: "
         << hash_bitset(h_bitset) << endl; 
} 
  
// To demonstrate Vector<bool> Hashing 
void vectorHashing() 
{ 
  
    // Get the Vector<bool> 
    // to get its hash value 
    vector<bool> 
        h_vecbool{ true, false, 
                   true, false }; 
  
    // Instatiation of Object 
    hash<vector<bool> > hash_vector_bool; 
  
    // Using operator() to get hash value 
    cout << "\nVector<bool> hash value: "
         << hash_vector_bool(h_vecbool) 
         << endl; 
} 
  
// To demonstrate Char Hashing 
void charHashing() 
{ 
  
    // Get the char 
    // to get its hash value 
    char ch = 'a'; 
  
    // Instatiation of Object 
    hash<char> hash_char; 
  
    // Using operator() to get hash value 
    cout << "\nChar hash values: "
         << hash_char(ch) 
         << endl; 
} 
  
// Driver Code 
int main() 
{ 
  
    stringHashing(); 
    bitsetHashing(); 
    vectorHashing(); 
    charHashing(); 
} 

template < class Key,                        // unordered_set::key_type/value_type
           class Hash = hash<Key>,           // unordered_set::hasher
           class Pred = equal_to<Key>,       // unordered_set::key_equal
           class Alloc = allocator<Key>      // unordered_set::allocator_type
           > class unordered_set;