29 Numerics library [numerics]

29.6 Random number generation [rand]

29.6.8 Random number distribution class templates [rand.dist]

29.6.8.2 Uniform distributions [rand.dist.uni]

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

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

P(i|a,b)=1/(ba+1).

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

    // constructors and reset functions
    explicit uniform_int_distribution(IntType a = 0, 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;
  };

explicit uniform_int_distribution(IntType a = 0, IntType b = numeric_limits<IntType>::max());

Requires: ab.

Effects: Constructs a uniform_­int_­distribution object; a and b correspond to the respective parameters of the distribution.

result_type a() const;

Returns: The value of the a parameter with which the object was constructed.

result_type b() const;

Returns: The value of the b parameter with which the object was constructed.

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

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

p(x|a,b)=1/(ba).

[Note: This implies that p(x|a,b) 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
    explicit uniform_real_distribution(RealType a = 0.0, 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;
  };

explicit uniform_real_distribution(RealType a = 0.0, RealType b = 1.0);

Requires: ab and banumeric_limits<RealType>::max().

Effects: Constructs a uniform_­real_­distribution object; a and b correspond to the respective parameters of the distribution.

result_type a() const;

Returns: The value of the a parameter with which the object was constructed.

result_type b() const;

Returns: The value of the b parameter with which the object was constructed.