std::subtract_with_carry_engine::subtract_with_carry_engine(3)

NAME
std::subtract_with_carry_engine::subtract_with_carry_engine - std::subtract_with_carry_engine::subtract_with_carry_engine

Synopsis
   subtract_with_carry_engine() : (1) (since C++11)
   subtract_with_carry_engine(0u) {}
   explicit subtract_with_carry_engine( result_type value ); (2) (since C++11)
   template< class SeedSeq > (3) (since C++11)
   explicit subtract_with_carry_engine( SeedSeq& seq );
   subtract_with_carry_engine( const (4) (since C++11)
   subtract_with_carry_engine& other ); (implicitly declared)
   Constructs the pseudo-random number engine.
   1) The default constructor.
   2) Constructs the engine with a seed value value. The sequence X of the engine's
   initial state is determined as follows:
    1. Constructs a std::linear_congruential_engine<std::uint_least32_t, 40014u, 0u,
       2147483563u> object e with argument value == 0u ? default_seed : value.
    2. Let n be std::size_t(w / 32) + 1.
    3. Sets the values of \(X_{-r}\)X
       -r, ..., \(X_{-1}\)X
       -1, in that order. Each value \(X_i\)X
       i is set as specified below:
    1. Successively calls e for n times, the return values are denoted as \(z_0\)z
       0 ... \(z_{n-1}\)z
       n-1.
    2. Sets \(X_i\)X
       i to \((\sum^{n-1}_{j=0} z_j \cdot 2^{32j}) \mod m\)(∑n-1
       j=0 z
       j·232j
       ) mod m.
   If \(X_{-1}\)X
   -1 is 0, sets the carry value c of the engine's initial state to 1. Otherwise, sets
   c to 0.
   3) Constructs the engine with a seed sequence seq. Given std::size_t(w / 32) + 1 as
   k, the sequence X of the engine's initial state is determined as follows:
    1. Creates an invented array object a of length r * k.
    2. Calls seq.generate(a + 0, a + r * k).
    3. For each integer i in [-r, -1], sets \(X_{i}\)X
       i to \((\sum^{k-1}_{j=0} a_{k(i+r)+j} \cdot 2^{32j}) \mod m\)(∑k-1
       j=0 a
       k(i+r)+j·232j
       ) mod m.
   If \(X_{-1}\)X
   -1 is 0, sets the carry value c of the engine's initial state to 1. Otherwise, sets
   c to 0.
   This overload participates in overload resolution only if SeedSeq meets the
   requirements of SeedSequence.
   4) The copy constructor. Upon construction, *this == other is true.

Parameters
   value - seed value to use in the initialization of the internal state
   seq - seed sequence to use in the initialization of the internal state

Complexity
   1,2) (std::size_t(w / 32) + 1) * r invocations of e.
   3) Same as the complexity of the seq.generate call.
   4) \(\small{O(r)}\)O(r).
   Defect reports
   The following behavior-changing defect reports were applied retroactively to
   previously published C++ standards.
      DR Applied to Behavior as published Correct behavior
   LWG 3809 C++11 e could not be constructed if e can be constructed in
                       result_type is std::uint16_t this case
   P0935R0 C++11 the default constructor was explicit made implicit

See also
   seed sets the current state of the engine
   (C++11) (public member function)