Defined in header <random> | ||
|---|---|---|
template< class RealType = double > class uniform_real_distribution; | (since C++11) |
Produces random floating-point values i, uniformly distributed on the interval [a, b), that is, distributed according to the probability density function: P(i|a,b) =
| 1 |
| b − a |
std::uniform_real_distribution satisfies all requirements of RandomNumberDistribution.
| RealType | - | The result type generated by the generator. The effect is undefined if this is not one of float, double, or long double. |
| Member type | Definition |
|---|---|
result_type | RealType |
param_type | the type of the parameter set, see RandomNumberDistribution. |
| constructs new distribution (public member function) |
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| resets the internal state of the distribution (public member function) |
|
Generation |
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| generates the next random number in the distribution (public member function) |
|
Characteristics |
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| returns the distribution parameters (public member function) |
|
| gets or sets the distribution parameter object (public member function) |
|
| returns the minimum potentially generated value (public member function) |
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| returns the maximum potentially generated value (public member function) |
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| compares two distribution objects (function) |
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| performs stream input and output on pseudo-random number distribution (function template) |
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. This is caused by LWG issue 2524
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
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