unordered_set::max_load_factor

Gets or sets the maximum elements per bucket.

float max_load_factor() const;
void max_load_factor(float factor);

Parameters

• factor
  The new maximum load factor.

Remarks

The first member function returns the stored maximum load factor. The second member function replaces the stored maximum load factor with factor.

Example

// std_tr1__unordered_set__unordered_set_max_load_factor.cpp 
// compile with: /EHsc 
#include <unordered_set> 
#include <iostream> 
 
typedef std::unordered_set<char> Myset; 
int main() 
    { 
    Myset c1; 
 
    c1.insert('a'); 
    c1.insert('b'); 
    c1.insert('c'); 
 
// display contents " [c] [b] [a]" 
    for (Myset::const_iterator it = c1.begin(); 
        it != c1.end(); ++it) 
        std::cout << " [" << *it << "]"; 
    std::cout << std::endl; 
 
// inspect current parameters 
    std::cout << "bucket_count() == " << c1.bucket_count() << std::endl; 
    std::cout << "load_factor() == " << c1.load_factor() << std::endl; 
    std::cout << "max_bucket_count() == " 
        << c1.max_bucket_count() << std::endl; 
    std::cout << "max_load_factor() == " 
        << c1.max_load_factor() << std::endl; 
    std::cout << std::endl; 
 
// change max_load_factor and redisplay 
    c1.max_load_factor(0.10f); 
    std::cout << "bucket_count() == " << c1.bucket_count() << std::endl; 
    std::cout << "load_factor() == " << c1.load_factor() << std::endl; 
    std::cout << "max_bucket_count() == " 
        << c1.max_bucket_count() << std::endl; 
    std::cout << "max_load_factor() == " 
        << c1.max_load_factor() << std::endl; 
    std::cout << std::endl; 
 
// rehash and redisplay 
    c1.rehash(100); 
    std::cout << "bucket_count() == " << c1.bucket_count() << std::endl; 
    std::cout << "load_factor() == " << c1.load_factor() << std::endl; 
    std::cout << "max_bucket_count() == " 
        << c1.max_bucket_count() << std::endl; 
    std::cout << "max_load_factor() == " 
        << c1.max_load_factor() << std::endl; 
    std::cout << std::endl; 
 
    return (0); 
    } 
 

 [c] [b] [a]
bucket_count() == 8
load_factor() == 0.375
max_bucket_count() == 8
max_load_factor() == 4

bucket_count() == 8
load_factor() == 0.375
max_bucket_count() == 8
max_load_factor() == 0.1

bucket_count() == 128
load_factor() == 0.0234375
max_bucket_count() == 128
max_load_factor() == 0.1

Requirements

Header: <unordered_set>

Namespace: std

See Also

Reference

<unordered_set>

unordered_set Class

unordered_set::load_factor

unordered_set::rehash