hash_map::rehash (STL/CLR)

Articolo
03/05/2013

Ricompila la tabella hash.

    void rehash();

Note

La funzione membro ricompila la tabella hash, e il hash_map::load_factor (STL/CLR)() <=hash_map::max_load_factor (STL/CLR).In caso contrario, il hash la tabella aumenta di dimensioni solo in base alle esigenze dopo un inserimento.(Mai automaticamente o riduzione delle dimensioni.) Utilizzarla per regolare le dimensioni della tabella hash.

Esempio

// cliext_hash_map_rehash.cpp 
// compile with: /clr 
#include <cliext/hash_map> 
 
typedef cliext::hash_map<wchar_t, int> Myhash_map; 
int main() 
    { 
    Myhash_map c1 = gcnew Myhash_map; 
    c1.insert(Myhash_map::make_value(L'a', 1)); 
    c1.insert(Myhash_map::make_value(L'b', 2)); 
    c1.insert(Myhash_map::make_value(L'c', 3)); 
 
// display contents " [a 1] [b 2] [c 3]" 
    for each (Myhash_map::value_type elem in c1) 
        System::Console::Write(" [{0} {1}]", elem->first, elem->second); 
    System::Console::WriteLine(); 
 
// inspect current parameters 
    System::Console::WriteLine("bucket_count() = {0}", c1.bucket_count()); 
    System::Console::WriteLine("load_factor() = {0}", c1.load_factor()); 
    System::Console::WriteLine("max_load_factor() = {0}", 
        c1.max_load_factor()); 
    System::Console::WriteLine(); 
 
// change max_load_factor and redisplay 
    c1.max_load_factor(0.25f); 
    System::Console::WriteLine("bucket_count() = {0}", c1.bucket_count()); 
    System::Console::WriteLine("load_factor() = {0}", c1.load_factor()); 
    System::Console::WriteLine("max_load_factor() = {0}", 
        c1.max_load_factor()); 
    System::Console::WriteLine(); 
 
// rehash and redisplay 
    c1.rehash(100); 
    System::Console::WriteLine("bucket_count() = {0}", c1.bucket_count()); 
    System::Console::WriteLine("load_factor() = {0}", c1.load_factor()); 
    System::Console::WriteLine("max_load_factor() = {0}", 
        c1.max_load_factor()); 
    return (0); 
    }