< cpp‎ | numeric‎ | random
Pseudo-random number generation
Uniform random bit generators
Engines and engine adaptors
Non-deterministic generator
Uniform distributions
Bernoulli distributions
Poisson distributions
Normal distributions
Sampling distributions
Seed Sequences
C library
Defined in header <random>
template< class RealType = double >
class uniform_real_distribution;
(since C++11)

Produces random floating-point values x, uniformly distributed on the interval [a, b), that is, distributed according to the probability density function:

P(x|a,b) =
b − a

std::uniform_real_distribution satisfies all requirements of RandomNumberDistribution


[edit] Template parameters

RealType - The result type generated by the generator. The effect is undefined if this is not one of float, double, or long double.

[edit] Member types

Member type Definition
result_type(C++11) RealType
param_type(C++11) the type of the parameter set, see RandomNumberDistribution.

[edit] Member functions

constructs new distribution
(public member function) [edit]
resets the internal state of the distribution
(public member function) [edit]
generates the next random number in the distribution
(public member function) [edit]
returns the distribution parameters
(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

(C++11)(C++11)(removed in C++20)
compares two distribution objects
(function) [edit]
performs stream input and output on pseudo-random number distribution
(function template) [edit]

[edit] Notes

To create a distribution over the closed interval [a, b], std::nextafter(b, std::numeric_limits<RealType>::max()) may be used as the second parameter.

Some existing implementations have a bug where they may occasionally return b if RealType is float GCC #63176 LLVM #18767 MSVC STL #1074. This is caused by LWG issue 2524.

[edit] Example

print 10 random numbers between 1 and 2

#include <random>
#include <iostream>
int main()
    std::random_device rd;  //Will be used to obtain a seed for the random number engine
    std::mt19937 gen(rd()); //Standard mersenne_twister_engine seeded with rd()
    std::uniform_real_distribution<> dis(1.0, 2.0);
    for (int n = 0; n < 10; ++n) {
        // Use dis to transform the random unsigned int generated by gen into a 
        // double in [1, 2). Each call to dis(gen) generates a new random double
        std::cout << dis(gen) << ' ';
    std::cout << '\n';

Possible output:

1.80829 1.15391 1.18483 1.38969 1.36094 1.0648 1.97798 1.27984 1.68261 1.57326