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std::discrete_distribution

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< cpp‎ | numeric‎ | random
 
 
 
Pseudo-random number generation
Engines and engine adaptors
Generators
Distributions
Uniform distributions
Bernoulli distributions
Poisson distributions
Normal distributions
Sampling distributions
discrete_distribution
(C++11)
Seed Sequences
(C++11)
C library
 
 
Defined in header <random>
template< class IntType = int >
class discrete_distribution;
(since C++11)

std::discrete_distribution produces random integers on the interval [0, n), where the probability of each individual integer i is defined as w
i
/S
, that is the weight of the ith integer divided by the sum of all n weights.

Contents

[edit] Member types

Member type Definition
result_type IntType
param_type the type of the parameter set, unspecified

[edit] Member functions

constructs new distribution
(public member function) [edit]
resets the internal state of the distribution
(public member function) [edit]
Generation
generates the next random number in the distribution
(public member function) [edit]
Characteristics
obtains the list of probabilities
(public member function) [edit]
gets or sets the distribution parameter object
(public member function) [edit]
returns the minimum potentially generated value
(public member function) [edit]
returns the maximum potentially generated value
(public member function) [edit]

[edit] Non-member functions

compares two distribution objects
(function) [edit]
performs stream input and output on pseudo-random number distribution
(function) [edit]

[edit] Example

#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> m;
    for(int n=0; n<10000; ++n) {
        ++m[d(gen)];
    }
    for(auto p : m) {
        std::cout << p.first << " generated " << p.second << " times\n";
    }
}

Output:

0 generated 4028 times
1 generated 978 times
2 generated 1012 times
3 generated 3982 times