unordered_map::max_load_factor

Articolo
02/19/2013

Ottiene o imposta elementi massimo per bucket.

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

Parametri

factor
il nuovo fattore di carico massimo.

Note

la prima funzione membro restituisce il fattore di carico massimo archiviato.La seconda funzione membro sostituisce il fattore di carico massimo archiviato con factor.

Esempio

// std_tr1__unordered_map__unordered_map_max_load_factor.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; 
 
// 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); 
    }