hash_map::max_load_factor (STL/CLR)

[アーティクル]
06/05/2017

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The latest version of this topic can be found at hash_map::max_load_factor (STL/CLR).

Gets or sets the maximum elements per bucket.

Syntax

float max_load_factor();  
void max_load_factor(float new_factor);

Parameters

new_factor
New maximum load factor to store.

Remarks

The first member function returns the current stored maximum load factor. You use it to determine the maximum average bucket size.

The second member function replaces the store maximum load factor with new_factor. No automatic rehashing occurs until a subsequent insert.

Example

// cliext_hash_map_max_load_factor.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);   
    }

 [a 1] [b 2] [c 3]  
bucket_count
() = 16  
load_factor
() = 0.1875  
max_load_factor
() = 4  
  
bucket_count
() = 16  
load_factor
() = 0.1875  
max_load_factor
() = 0.25  
  
bucket_count
() = 128  
load_factor
() = 0.0234375  
max_load_factor
() = 0.25

Requirements

Header: <cliext/hash_map>

Namespace: cliext

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