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## Class param_type

boost::random::extreme_value_distribution::param_type

## Synopsis

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

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

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

## Description

### `param_type` public construct/copy/destruct

1.     explicit param_type(RealType a = 1.0, RealType b = 1.0);

   Constructs a ``param_type`` from the "a" and "b" parameters of the distribution.

   Requires: b > 0

### `param_type` public member functions

1.     RealType a() const;

   Returns the "a" parameter of the distribtuion.

2.     RealType b() const;

   Returns the "b" parameter of the distribution.

### `param_type` friend functions

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

   Writes a ``param_type`` to a `std::ostream`.

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

   Reads a ``param_type`` from a `std::istream`.

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

   Returns true if the two sets of parameters are the same.

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

   Returns true if the two sets of parameters are the different.