std::bernoulli_distribution(3)

NAME
std::bernoulli_distribution - std::bernoulli_distribution

Synopsis
   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.

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

Member functions
   constructor constructs new distribution
   (C++11) (public member function)
   reset resets the internal state of the distribution
   (C++11) (public member function)

Generation
   operator() generates the next random number in the distribution
   (C++11) (public member function)

Characteristics
   p returns the p distribution parameter (probability of generating true)
   (C++11) (public member function)
   param gets or sets the distribution parameter object
   (C++11) (public member function)
   min returns the minimum potentially generated value
   (C++11) (public member function)
   max returns the maximum potentially generated value
   (C++11) (public member function)

Non-member functions
   operator==
   operator!= compares two distribution objects
   (C++11) (function)
   (C++11)(removed in C++20)
   operator<< performs stream input and output on pseudo-random number
   operator>> distribution
   (C++11) (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.