std::discrete_distribution::discrete_distribution
discrete_distribution(); 
(1)  (since C++11) 
template< class InputIt > discrete_distribution( InputIt first, InputIt last ); 
(2)  (since C++11) 
discrete_distribution( std::initializer_list<double> weights ); 
(3)  (since C++11) 
template< class UnaryOperation > discrete_distribution( std::size_t count, double xmin, double xmax, 
(4)  (since C++11) 
explicit discrete_distribution( const param_type& params ); 
(2)  (since C++11) 
Constructs a new distribution object.
1) Default constructor. Constructs the distribution with weights . This distribution will always generate 0.
2) Constructs the distribution with weights in the range [first, last)
. If first == last, the effects are the same as of the default constructor.
3) Constructs the distribution with weights in weights
. Effectively calls initializer_list(weigths.begin(), weights.end()).
count
weights that are generated using function unary_op
. Each of the weights is equal to wi = unary_op(xmin + δ/2 + i · δ), where δ =
(xmax − xmin) 
count 
xmin
and xmax
must be such that δ > 0. If count == 0 the effects are the same as of the default constructor.
5) Constructs the distribution with params
as the distribution parameters.
Parameters
first, last    the range of elements defining the numbers to use as weights. The type of the elements referred by InputIterator must be convertible to double

weights    initializer list containing the weights 
unary_op    unary operation function object that will be applied. The signature of the function should be equivalent to the following: Ret fun(const Type &a); The signature does not need to have const &. 
params    the distribution parameter set 
Type requirements  
InputIt must meet the requirements of InputIterator .
