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# binomial_distribution::operator()

Visual Studio 2008

Returns a random value.

```template<class Engine>
result_type operator()(Engine& eng);
```

## Parameters

Engine

The type of the random engine.

eng

The random engine.

## Remarks

The member function uses the engine eng as a source of uniformly distributed random integral values and returns integral values with each value i occuring with probability pr(i) = comb(stored_t, i) * stored_pi * (1 - stored_p)stored_t-i, where comb(t, i) is the number of possible combinations of t objects taken i at a time.

## Example

```// std_tr1__random__binomial_distribution_operator_fn.cpp
// compile with: /EHsc
#include <random>
#include <iostream>

typedef std::tr1::mt19937 Myeng;
typedef std::tr1::binomial_distribution<int, double> Mydist;
int main()
{
Myeng eng;
Mydist dist(2, 0.6);
Mydist::input_type engval = eng();
Mydist::result_type distval = dist(eng);

distval = distval;  // to quiet "unused" warnings
engval = engval;

std::cout << "p == " << dist.p() << std::endl;
std::cout << "t == " << dist.t() << std::endl;

dist.reset(); // discard any cached values
std::cout << "a random value == " << dist(eng) << std::endl;
std::cout << "a random value == " << dist(eng) << std::endl;
std::cout << "a random value == " << dist(eng) << std::endl;

return (0);
}

```
p == 0.6 t == 2 a random value == 1 a random value == 0 a random value == 1