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operator<<,>>(std::mersenne_twister_engine)

template< class CharT, class Traits >
friend std::basic_ostream<CharT,Traits>& 
    operator<<( std::basic_ostream<CharT,Traits>& ost, 
                const mersenne_twister_engine& e );

(1)

(since C++11)

template< class CharT, class Traits >
friend std::basic_istream<CharT,Traits>& 
    operator>>( std::basic_istream<CharT,Traits>& ist, 
                mersenne_twister_engine& e );

(2)

(since C++11)

1) Serializes the internal state of the pseudo-random number engine e as a sequence of decimal numbers separated by one or more spaces, and inserts it to the stream ost. The fill character and the formatting flags of the stream are ignored and unaffected.

2) Restores the internal state of the pseudo-random number engine e from the serialized representation, which was created by an earlier call to operator<< using a stream with the same imbued locale and the same CharT and Traits. If the input cannot be deserialized, e is left unchanged and failbit is raised on ist.

These function templates are not visible to ordinary unqualified or qualified lookup, and can only be found by argument-dependent lookup when std::mersenne_twister_engine<UIntType,w,n,m,r,a,u,d,s,b,t,c,l,f> is an associated class of the arguments.

If a textual representation is written using os << x and that representation is restored into the same or a different object y of the same type using is >> y, then x == y.

The textual representation is written with os.fmtflags set to ios_base::dec|ios_base::left and the fill character set to the space character. The textual representation of the engine's internal state is a set of decimal numbers separated by spaces.

Parameters

ost	-	output stream to insert the data to
ist	-	input stream to extract the data from
e	-	pseudo-random number engine

Return value

1) ost

2) ist

Complexity

Exceptions

1) May throw implementation-defined exceptions.

2) May throw std::ios_base::failure when setting failbit.

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 3519	C++11	the form of insertion and extraction operators were unspecified	specified to be hidden friends

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