26 Numerics library [numerics]

26.5 Random number generation [rand]

26.5.8 Random number distribution class templates [rand.dist]

26.5.8.3 Bernoulli distributions [rand.dist.bern]

26.5.8.3.2 Class template binomial_distribution [rand.dist.bern.bin]

1

A binomial_distribution random number distribution produces integer values i ≥ 0 distributed according to the discrete probability function \[% P(i\,|\,t,p) = \binom{t}{i} \cdot p^i \cdot (1-p)^{t-i} \; \mbox{.} \]

template<class IntType = int>
 class binomial_distribution{
public:
 // types
 typedef IntType result_type;
 typedef unspecified param_type;

 // constructors and reset functions
 explicit binomial_distribution(IntType t = 1, double p = 0.5);
 explicit binomial_distribution(const param_type& parm);
 void reset();

 // generating functions
 template<class URNG>
   result_type operator()(URNG& g);
 template<class URNG>
   result_type operator()(URNG& g, const param_type& parm);

 // property functions
 IntType t() const;
 double p() const;
 param_type param() const;
 void param(const param_type& parm);
 result_type min() const;
 result_type max() const;
};

explicit binomial_distribution(IntType t = 1, double p = 0.5);

2

Requires: 0 ≤ p ≤ 1 and 0 ≤ t .

3

Effects: Constructs a binomial_distribution object; t and p correspond to the respective parameters of the distribution.

IntType t() const;

4

Returns: The value of the t parameter with which the object was constructed.

double p() const;

5

Returns: The value of the p parameter with which the object was constructed.