C++ Unordered_set Library - max_load_factor

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Description

It is used to get or set maximum load factor.

Declaration

Following is the declaration for std::unordered_set::max_load_factor.

C++11

float max_load_factor() const noexcept;
void max_load_factor ( float z );

Parameters

z − This is the new maximum load factor.

Return value

It returns the current load factor.

Exceptions

Exception is thrown if any element comparison object throws exception.

Please note that invalid arguments cause undefined behavior.

Time complexity

constant time.

Example

The following example shows the usage of std::unordered_set::max_load_factor.

#include <iostream>
#include <string>
#include <unordered_set>

int main () {
   std::unordered_set<std::string> myset =
      {"sai", "Ram", "krishna", "prasad", "Bangalore", "india"};

   std::cout << "current max_load_factor: " << myset.max_load_factor() << std::endl;
   std::cout << "current size: " << myset.size() << std::endl;
   std::cout << "current bucket_count: " << myset.bucket_count() << std::endl;
   std::cout << "current load_factor: " << myset.load_factor() << std::endl;

   float z = myset.max_load_factor();
   myset.max_load_factor ( z / 2.0 );
   std::cout << "[max_load_factor halved]" << std::endl;

   std::cout << "new max_load_factor: " << myset.max_load_factor() << std::endl;
   std::cout << "new size: " << myset.size() << std::endl;
   std::cout << "new bucket_count: " << myset.bucket_count() << std::endl;
   std::cout << "new load_factor: " << myset.load_factor() << std::endl;

   return 0;
}

Let us compile and run the above program, this will produce the following result −

current max_load_factor: 1
current size: 6
current bucket_count: 7
current load_factor: 0.857143
[max_load_factor halved]
new max_load_factor: 0.5
new size: 6
new bucket_count: 17
new load_factor: 0.352941