public member function
<random>

std::piecewise_constant_distribution::operator

(1)
template<class URNG>
result_type operator()(URNG& g);
(2)
template<class URNG>
result_type operator()(URNG& g, const param_type& parm);
Generate random number
Returns a new random number that follows the distribution's parameters associated to the object (version 1) or those specified by parm (version 2).

The generator object (g) supplies uniformly-distributed random integers through its operator() member function. The piecewise_constant_distribution object transforms the values obtained this way so that successive calls to this member function with the same arguments produce values that follow a piecewise constant distribution with the appropriate intervals and probability densities.

Parameters

g
A uniform random number generator object, used as the source of randomness.
URNG shall be a uniform random number generator type, such as one of the standard generator classes.
parm
An object representing the distribution's parameters (weights), obtained by a call to member function param.
param_type is a member type.

Return value

A new random number.
result_type is a member type, defined as an alias of the first class template parameter (RealType).

Example

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// piecewise_constant_distribution::operator()
#include <iostream>
#include <chrono>
#include <random>

int main()
{
  // construct a trivial random generator engine from a time-based seed:
  unsigned seed = std::chrono::system_clock::now().time_since_epoch().count();
  std::default_random_engine generator (seed);

  std::piecewise_constant_distribution<double> distribution ( 4, 0.0, 10.0, [](double x){return x;} );

  std::cout << "intervals : ";
  for (double x:distribution.intervals()) std::cout << x << " ";
  std::cout << std::endl;
  std::cout << "densities : ";
  for (double x:distribution.densities()) std::cout << x << " ";
  std::cout << std::endl;

  return 0;
}


Possible output:
intervals: 0 2.5 5. 7.5 10
densities: 0.025 0.075 0.125 0.175

Complexity

Amortized constant (a constant number of invocations of g.operator()).

See also