C++ named requirements: RandomNumberEngineAdaptor

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C++ named requirements

A RandomNumberEngineAdaptor is a RandomNumberEngine that transforms the output of another RandomNumberEngine, the latter of which is termed a base engine.



  • B, a RandomNumberEngine
  • b, an object of type B
  • A, a RandomNumberEngineAdaptor, adapting B as a base engine
  • a, an object of type A
function semantics
A::A(); The base engine is initialized as if by its default constructor.
bool operator==(const A& lhs, const A& rhs); Returns whether lhs's base engine is equal to rhs's base engine or not.
A::A(result_type s); The base engine is initialized with s.
template<class Sseq> A::A(Sseq& q); The base engine is initialized with q.
void seed(); Invokes b.seed().
void seed(result_type s); Invokes b.seed(s).
template<class Sseq> void seed(Sseq& q); Invokes b.seed(q).


  • The complexity of each function of A does not exceed the complexity of the function of B
  • The state of A includes the state of B
  • The size of A's state is no less than the size of b
  • Copying A's state includes copying B's state
  • The textual representation of A includes the textual representation of B

Standard library

The following standard library facilities satisfy RandomNumberEngineAdaptor:

discards some output of a random number engine
(class template)
packs the output of a random number engine into blocks of a specified number of bits
(class template)
delivers the output of a random number engine in a different order
(class template)