std::discrete_distribution
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discrete_distribution
(C++11)
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(C++11)
std::discrete_distribution
Member functions
Generation
Characteristics
Non-member functions
(C++11)(C++11)(until C++20)
(C++11)(C++11)
Defined in header
<random>
template< class IntType = int >
class discrete_distribution;
(since C++11)
class discrete_distribution;
std::discrete_distribution produces random integers on the interval [0, n), where the probability of each individual integer i is defined as wi/S, that is the weight of the ith integer divided by the sum of all n weights.
std::discrete_distribution satisfies all requirements of RandomNumberDistribution.
Contents
[edit] Template parameters
IntType
-
The result type generated by the generator. The effect is undefined if this is not one of short, int, long, long long, unsigned short, unsigned int, unsigned long, or unsigned long long.
[edit] Member types
Member type
Definition
result_type (C++11)
IntType
[edit] Member functions
Generation
Characteristics
[edit] Non-member functions
(C++11)
(function template) [edit]
[edit] Example
Run this code
#include <iomanip> #include <iostream> #include <map> #include <random> int main() { std::random_device rd; std::mt19937 gen(rd()); std::discrete_distribution<> d({40, 10, 10, 40}); std::map <int, int> map; for (int n = 0; n < 1e4; ++n) ++map[d(gen)]; for (const auto& [num, count] : map) std::cout << num << " generated " << std::setw (4) << count << " times\n"; }
Possible output:
0 generated 4037 times 1 generated 962 times 2 generated 1030 times 3 generated 3971 times