random_device::entropy
Estimates the randomness of the source.
double entropy() const;
Remarks
The member function returns an estimate of the randomness of the source, as measured in bits. (In the extreme, a non-random source has an entropy of zero.)
Example
// std_tr1__random__random_device_entropy.cpp
// compile with: /EHsc
#include <random>
#include <iostream>
typedef std::random_device Myceng;
int main()
{
Myceng ceng;
Myceng::result_type compval = ceng();
compval = compval; // to quiet "unused" warnings
std::cout << "entropy == " << ceng.entropy() << std::endl;
std::cout << "min == " << ceng.min() << std::endl;
std::cout << "max == " << ceng.max() << std::endl;
std::cout << "a random value == " << ceng() << std::endl;
std::cout << "a random value == " << ceng() << std::endl;
std::cout << "a random value == " << ceng() << std::endl;
return (0);
}
entropy == 0 min == 0 max == 4294967295 a random value == 2439379569 a random value == 2439379569 a random value == 2439379569
Requirements
Header: <random>
Namespace: std