unordered_map::bucket

Gets the bucket number for a key value.

size_type bucket(const Key& keyval) const;

Parameters

• keyval
  The key value to map.

Remarks

The member function returns the bucket number currently corresponding to the key value keyval.

Example

// std_tr1__unordered_map__unordered_map_bucket.cpp 
// compile with: /EHsc 
#include <unordered_map> 
#include <iostream> 
 
typedef std::unordered_map<char, int> Mymap; 
int main() 
    { 
    Mymap c1; 
 
    c1.insert(Mymap::value_type('a', 1)); 
    c1.insert(Mymap::value_type('b', 2)); 
    c1.insert(Mymap::value_type('c', 3)); 
 
// display contents " [c 3] [b 2] [a 1]" 
    for (Mymap::const_iterator it = c1.begin(); 
        it != c1.end(); ++it) 
        std::cout << " [" << it->first << ", " << it->second << "]"; 
    std::cout << std::endl; 
 
// display buckets for keys 
    Mymap::size_type bs = c1.bucket('a'); 
    std::cout << "bucket('a') == " << bs << std::endl; 
    std::cout << "bucket_size(" << bs << ") == " << c1.bucket_size(bs) 
        << std::endl; 
 
    return (0); 
    } 
 

 [c, 3] [b, 2] [a, 1]
bucket('a') == 7
bucket_size(7) == 1

Requirements

Header: <unordered_map>

Namespace: std

See Also

Reference

<unordered_map>

unordered_map Class

unordered_map::bucket_count

unordered_map::bucket_size