/C++

# 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 == true `
1 − p if `b == false`

`std::bernoulli_distribution` satisfies RandomNumberDistribution.

### Member types

Member type Definition
`result_type` `bool`
`param_type` the type of the parameter set, see RandomNumberDistribution.

### Member functions

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

### Non-member functions

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

### Example

```#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';
}
}```

Possible output:

```false ***************
true ****```

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