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std::negati...distribution(3)  C++ Standard Libary std::negati...distribution(3)

NAME
     std::negative_binomial_distribution - std::negative_binomial_distribution

Synopsis
	Defined in header <random>
	template< class IntType = int >        (since C++11)
	class negative_binomial_distribution;

	Produces  random non-negative integer values i, distributed according to
     discrete
	probability function:

	\(P(i|k, p) = \binom{k + i - 1}{i} \cdot p^k \cdot (1  -  p)^i\)P(i|k,p)
     =a
	a
	ak + i a 1
	ia
	a
	a  A. pk
	A. (1 a p)i

	The  value  represents the number of failures in a series of independent
     yes/no trials
	(each succeeds with probability p), before exactly k successes occur.

	std::negative_binomial_distribution satisfies RandomNumberDistribution.

Template parameters
		  The result type generated by the generator. The effect is  un-
     defined if
	IntType  -  this  is  not  one	of short, int, long, long long, unsigned
     short, unsigned
		  int, unsigned long, or unsigned long long.

Member types
	Member type	    Definition
	result_type (C++11) IntType
	param_type (C++11)  the type of the parameter set, see	RandomNumberDis-
     tribution.

Member functions
	constructor   constructs new distribution
	(C++11)       (public member function)
	reset	      resets the internal state of the distribution
	(C++11)       (public member function)

Generation
	operator()    generates the next random number in the distribution
	(C++11)       (public member function)

Characteristics
	p	      returns the distribution parameters
	k	      (public member function)
	(C++11)
	param	      gets or sets the distribution parameter object
	(C++11)       (public member function)
	min	      returns the minimum potentially generated value
	(C++11)       (public member function)
	max	      returns the maximum potentially generated value
	(C++11)       (public member function)

Non-member functions
	operator==
	operator!=		  compares two distribution objects
	(C++11) 		  (function)
	(C++11)(removed in C++20)
	operator<<		   performs  stream  input and output on pseudo-
     random number
	operator>>		  distribution
	(C++11) 		  (function template)

Example
     // Run this code

      #include <iomanip>
      #include <iostream>
      #include <map>
      #include <random>
      #include <string>

      int main()
      {
	  std::random_device rd;
	  std::mt19937 gen(rd());
	  // Pat goes door-to-door selling cookies
	  // At each house, there's a 75% chance that she sells one box
	  // how many times will she be turned away before selling 5 boxes?
	  std::negative_binomial_distribution<> d(5, 0.75);

	  std::map<int, int> hist;
	  for (int n = 0; n != 10000; ++n)
	      ++hist[d(gen)];

	  for (auto [x, y] : hist)
	      std::cout << std::hex << x << ' ' << std::string(y / 100, '*')  <<
     '\n';
      }

Possible output:
      0 ***********************
      1 *****************************
      2 **********************
      3 *************
      4 ******
      5 ***
      6 *
      7
      8
      9
      a
      b

External links
	Weisstein,  Eric W. "Negative Binomial Distribution." From MathWorld a A
     Wolfram Web
	Resource.

http://cppreference.com 	   2024.06.10	   std::negati...distribution(3)
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