24 Numerics library [numerics]

24.7 Random number generation [rand]

24.7.8 Random number distribution class templates [rand.dist]

24.7.8.2 Uniform distributions [rand.dist.uni]

24.7.8.2.1 Class template uniform_­int_­distribution [rand.dist.uni.int]

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A uniform_­int_­distribution random number distribution produces random integers i, , distributed according to the constant discrete probability function

template<class IntType = int>
  class uniform_int_distribution {
  public:
    // types
    using result_type = IntType;
    using param_type  = unspecified;

    // constructors and reset functions
    uniform_int_distribution() : uniform_int_distribution(0) {}
    explicit uniform_int_distribution(IntType a, IntType b = numeric_limits<IntType>::max());
    explicit uniform_int_distribution(const param_type& parm);
    void reset();

    // generating functions
    template<class URBG>
      result_type operator()(URBG& g);
    template<class URBG>
      result_type operator()(URBG& g, const param_type& parm);

    // property functions
    result_type a() const;
    result_type b() const;
    param_type param() const;
    void param(const param_type& parm);
    result_type min() const;
    result_type max() const;
  };
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explicit uniform_int_distribution(IntType a, IntType b = numeric_limits<IntType>::max());
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Requires: a≤b.
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Effects: Constructs a uniform_­int_­distribution object; a and b correspond to the respective parameters of the distribution.
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result_type a() const;
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Returns: The value of the a parameter with which the object was constructed.
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result_type b() const;
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Returns: The value of the b parameter with which the object was constructed.

24.7.8.2.2 Class template uniform_­real_­distribution [rand.dist.uni.real]

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#
A uniform_­real_­distribution random number distribution produces random numbers x, , distributed according to the constant probability density function

[ Note
:
This implies that is undefined when a == b.
— end note
 ]
template<class RealType = double>
  class uniform_real_distribution {
  public:
    // types
    using result_type = RealType;
    using param_type  = unspecified;

    // constructors and reset functions
    uniform_real_distribution() : uniform_real_distribution(0.0) {}
    explicit uniform_real_distribution(RealType a, RealType b = 1.0);
    explicit uniform_real_distribution(const param_type& parm);
    void reset();

    // generating functions
    template<class URBG>
      result_type operator()(URBG& g);
    template<class URBG>
      result_type operator()(URBG& g, const param_type& parm);

    // property functions
    result_type a() const;
    result_type b() const;
    param_type param() const;
    void param(const param_type& parm);
    result_type min() const;
    result_type max() const;
  };
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explicit uniform_real_distribution(RealType a, RealType b = 1.0);
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#
Requires: a≤b and b.
3
#
Effects: Constructs a uniform_­real_­distribution object; a and b correspond to the respective parameters of the distribution.
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result_type a() const;
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Returns: The value of the a parameter with which the object was constructed.
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result_type b() const;
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Returns: The value of the b parameter with which the object was constructed.