std::bernoulli_distribution

 

C++

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C library

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RAND_MAX

 

std::bernoulli_distribution

Member functions

bernoulli_distribution::bernoulli_distribution

bernoulli_distribution::reset

Generation

bernoulli_distribution::operator()

Characteristics

bernoulli_distribution::param

bernoulli_distribution::min

bernoulli_distribution::max

Non-member functions

operator== operator!=

operator<< operator>>

 

Defined in header <random>
class bernoulli_distribution;		(since C++11)

Produces random boolean values, according to the discrete probability function. The probability of true is

P(b|p) =⎧
⎨
⎩p if b == true 
1 − p if b == false

Member types

Member type	Definition
result_type	bool
param_type	the type of the parameter set, unspecified

Member functions

(constructor)	constructs new distribution (public member function)
reset	resets the internal state of the distribution (public member function)
Generation
operator()	generates the next random number in the distribution (public member function)
Characteristics
p	returns the p distribution parameter (probability of generating true) (public member function)
param	gets or sets the distribution parameter object (public member function)
min	returns the minimum potentially generated value (public member function)
max	returns the maximum potentially generated value (public member function)

Non-member functions

operator== operator!=	compares two distribution objects (function)
operator<< operator>>	performs stream input and output on pseudo-random number distribution (function)

Example

run this code

#include <iostream>
#include <iomanip>
#include <string>
#include <map>
#include <random>
 
int main()
{
    std::random_device rd;
    std::mt19937 gen(rd());
    // give "true" 1/4 of the time
    // give "false" 3/4 of the time
    std::bernoulli_distribution d(0.25);
 
    std::map<bool, int> hist;
    for(int n=0; n<10000; ++n) {
        ++hist[d(gen)];
    }
    for(auto p : hist) {
        std::cout << std::boolalpha << std::setw(5) << p.first
                  << ' ' << std::string(p.second/500, '*') << '\n';
    }
}

Output:

false ***************
 true ****

External links

Weisstein, Eric W. "Bernoulli Distribution." From MathWorld--A Wolfram Web Resource.