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std:: bernoulli_distribution

From cppreference.net
C++
Numerics library
Pseudo-random number generation
Random number distributions
Uniform distributions
(C++11)
(C++11)
(C++11)
Bernoulli distributions
bernoulli_distribution
(C++11)
(C++11)
(C++11)
(C++11)
Poisson distributions
(C++11)
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Normal distributions
(C++11)
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Sampling distributions
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std::bernoulli_distribution
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 is true
1 − p , if b is false

std::bernoulli_distribution satisfies RandomNumberDistribution .

Contents

Member types

Member type Definition
result_type (C++11) bool
param_type (C++11) the type of the parameter set, see RandomNumberDistribution .

Member functions

(C++11)
constructs new distribution
(public member function)
(C++11)
resets the internal state of the distribution
(public member function)
Generation
(C++11)
generates the next random number in the distribution
(public member function)
Characteristics
(C++11)
returns the p distribution parameter (probability of generating true )
(public member function)
(C++11)
gets or sets the distribution parameter object
(public member function)
(C++11)
returns the minimum potentially generated value
(public member function)
(C++11)
returns the maximum potentially generated value
(public member function)

Non-member functions

(C++11) (C++11) (removed in C++20)
compares two distribution objects
(function)
(C++11)
performs stream input and output on pseudo-random number distribution
(function template)

Example

Run this code 
#include <iomanip>
#include <iostream>
#include <map>
#include <random>
#include <string>
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)];
    std::cout << std::boolalpha;
    for (auto const& [key, value] : hist)
        std::cout << std::setw(5) << key << ' '
                  << std::string(value / 500, '*') << '\n';
}

Possible output: 

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

External links

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