| Home | Libraries | People | FAQ | More

## Class template uniform_real_distribution

boost::random::uniform_real_distribution

## Synopsis

    // In header: <boost/random/uniform_real_distribution.hpp>

    template<typename RealType = double>
    class uniform_real_distribution {
    public:
      // types
      typedef RealType input_type;
      typedef RealType result_type;

      // member classes/structs/unions

      class param_type {
      public:
        // types
        typedef uniform_real_distribution distribution_type;

        // construct/copy/destruct
        explicit param_type(RealType = 0.0, RealType = 1.0);

        // public member functions
        RealType a() const;
        RealType b() const;

        // friend functions
        template<typename CharT, typename Traits>
          friend std::basic_ostream< CharT, Traits > &
          operator<<(std::basic_ostream< CharT, Traits > &, const param_type &);
        template<typename CharT, typename Traits>
          friend std::basic_istream< CharT, Traits > &
          operator>>(std::basic_istream< CharT, Traits > &, const param_type &);
        friend bool operator==(const param_type &, const param_type &);
        friend bool operator!=(const param_type &, const param_type &);
      };

      // construct/copy/destruct
      explicit uniform_real_distribution(RealType = 0.0, RealType = 1.0);
      explicit uniform_real_distribution(const param_type &);

      // public member functions
      RealType min() const;
      RealType max() const;
      RealType a() const;
      RealType b() const;
      param_type param() const;
      void param(const param_type &);
      void reset();
      template<typename Engine> result_type operator()(Engine &) const;
      template<typename Engine>
        result_type operator()(Engine &, const param_type &) const;

      // friend functions
      template<typename CharT, typename Traits>
        friend std::basic_ostream< CharT, Traits > &
        operator<<(std::basic_ostream< CharT, Traits > &,
                   const uniform_real_distribution &);
      template<typename CharT, typename Traits>
        friend std::basic_istream< CharT, Traits > &
        operator>>(std::basic_istream< CharT, Traits > &,
                   const uniform_real_distribution &);
      friend bool operator==(const uniform_real_distribution &,
                             const uniform_real_distribution &);
      friend bool operator!=(const uniform_real_distribution &,
                             const uniform_real_distribution &);
    };

## Description

The class template uniform_real_distribution models a random distribution . On each invocation, it returns a random floating-point value uniformly distributed in the range [min..max).

### `uniform_real_distribution` public construct/copy/destruct

1.     explicit uniform_real_distribution(RealType min = 0.0, RealType max = 1.0);

   Constructs a `uniform_real_distribution`. `min` and `max` are the parameters of the distribution.

   Requires: min <= max

2.     explicit uniform_real_distribution(const param_type & param);

   Constructs a `uniform_real_distribution` from its parameters.

### `uniform_real_distribution` public member functions

1.     RealType min() const;

   Returns the minimum value of the distribution

2.     RealType max() const;

   Returns the maximum value of the distribution

3.     RealType a() const;

   Returns the minimum value of the distribution

4.     RealType b() const;

   Returns the maximum value of the distribution

5.     param_type param() const;

   Returns the parameters of the distribution.

6.     void param(const param_type & param);

   Sets the parameters of the distribution.

7.     void reset();

   Effects: Subsequent uses of the distribution do not depend on values produced by any engine prior to invoking reset.

8.     template<typename Engine> result_type operator()(Engine & eng) const;

   Returns a value uniformly distributed in the range [min, max).

9.     template<typename Engine>
         result_type operator()(Engine & eng, const param_type & param) const;

   Returns a value uniformly distributed in the range [param.a(), param.b()).

### `uniform_real_distribution` friend functions

1.     template<typename CharT, typename Traits>
         friend std::basic_ostream< CharT, Traits > &
         operator<<(std::basic_ostream< CharT, Traits > & os,
                    const uniform_real_distribution & ud);

   Writes the distribution to a `std::ostream`.

2.     template<typename CharT, typename Traits>
         friend std::basic_istream< CharT, Traits > &
         operator>>(std::basic_istream< CharT, Traits > & is,
                    const uniform_real_distribution & ud);

   Reads the distribution from a `std::istream`.

3.     friend bool operator==(const uniform_real_distribution & lhs,
                              const uniform_real_distribution & rhs);

   Returns true if the two distributions will produce identical sequences of values given equal generators.

4.     friend bool operator!=(const uniform_real_distribution & lhs,
                              const uniform_real_distribution & rhs);

   Returns true if the two distributions may produce different sequences of values given equal generators.