NAME¶

std::uniform_int_distribution - std::uniform_int_distribution

Synopsis¶

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

Produces random integer values \(\small i\)i, uniformly distributed on the closed
interval \(\small[a, b]\)[a, b], that is, distributed according to the discrete
probability function

\({\small P(i|a,b) =}\frac{1}{b - a + 1}\)P(i|a,b) =

1
b − a + 1

.

std::uniform_int_distribution satisfies all requirements of
RandomNumberDistribution.

Template parameters¶

The result type generated by the generator. The effect is undefined 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 RandomNumberDistribution.

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¶

a returns the distribution parameters
b (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¶

This program simulates throwing 6-sided dice.

// Run this code

#include <iostream>
#include <random>

int main()
{
std::random_device rd; // a seed source for the random number engine
std::mt19937 gen(rd()); // mersenne_twister_engine seeded with rd()
std::uniform_int_distribution<> distrib(1, 6);

// Use distrib to transform the random unsigned int
// generated by gen into an int in [1, 6]
for (int n = 0; n != 10; ++n)
std::cout << distrib(gen) << ' ';
std::cout << '\n';
}

Possible output:¶

1 1 6 5 2 2 5 5 6 2