poisson_distribution::poisson_distribution

Constructs the distribution.

poisson_distribution(RealType mean0 = RealType(1.0));
explicit binomial_distribution(const param_type& par0);

Parameters

• mean0
  The mean distribution parameter.

• par0
  The parameter package used to construct the distribution.

Remarks

Precondition: 0.0 < mean0

The first constructor constructs an object whose stored value stored_mean holds the value mean0.

The second constructor constructs an object whose stored parameters are initialized from par0.

Example

// std_tr1__random__poisson_distribution_construct.cpp 
// compile with: /EHsc 
#include <random> 
#include <iostream> 
 
typedef std::mt19937 Myeng; 
typedef std::poisson_distribution<int, double> Mydist; 
int main() 
    { 
    Myeng eng; 
    Mydist dist(3.5); 
    Mydist::input_type engval = eng(); 
    Mydist::result_type distval = dist(eng); 
 
    distval = distval;  // to quiet "unused" warnings 
    engval = engval; 
 
    std::cout << "mean == " << dist.mean() << 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); 
    } 
 

mean == 3.5
a random value == 5
a random value == 2
a random value == 11

Requirements

Header: <random>

Namespace: std

See Also

Reference

<random>

poisson_distribution Class