class template
<random>

std::uniform_real_distribution

template <class RealType = double> class uniform_real_distribution;
Uniform real distribution
Random number distribution that produces floating-point values according to a uniform distribution, which is described by the following probability density function:



This distribution (also know as rectangular distribution) produces random numbers in a range [a,b) where all intervals of the same length within it are equally probable.

The distribution parameters, a and b, are set on construction.

To produce a random value following this distribution, call its member function operator().

Template parameters

RealType
A floating-point type. Aliased as member type result_type.
By default, this is double.

Member types

The following aliases are member types of uniform_real_distribution:

member typedefinitionnotes
result_typeThe first template parameter (RealType)The type of the numbers generated (defaults to double)
param_typenot specifiedThe type returned by member param.

Member functions


Distribution parameters:


Non-member functions


Example

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// uniform_real_distribution
#include <iostream>
#include <random>

int main()
{
  const int nrolls=10000;  // number of experiments
  const int nstars=95;     // maximum number of stars to distribute
  const int nintervals=10; // number of intervals

  std::default_random_engine generator;
  std::uniform_real_distribution<double> distribution(0.0,1.0);

  int p[nintervals]={};

  for (int i=0; i<nrolls; ++i) {
    double number = distribution(generator);
    ++p[int(nintervals*number)];
  }

  std::cout << "uniform_real_distribution (0.0,1.0):" << std::endl;
  std::cout << std::fixed; std::cout.precision(1);

  for (int i=0; i<nintervals; ++i) {
    std::cout << float(i)/nintervals << "-" << float(i+1)/nintervals << ": ";
    std::cout << std::string(p[i]*nstars/nrolls,'*') << std::endl;
  }

  return 0;
}

Possible output:
uniform_real_distribution (0.0,1.0):
0.0-0.1: *********
0.1-0.2: *********
0.2-0.3: *********
0.3-0.4: *********
0.4-0.5: *********
0.5-0.6: *********
0.6-0.7: *********
0.7-0.8: *********
0.8-0.9: *********
0.9-1.0: *********


See also