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

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std::subtract_with_carry_engine
template < class CharT, class Traits >

friend std:: basic_ostream < CharT, Traits > &
operator << ( std:: basic_ostream < CharT, Traits > & os,

const subtract_with_carry_engine & e ) ;
(1) (since C++11)
template < class CharT, class Traits >

friend std:: basic_istream < CharT, Traits > &
operator >> ( std:: basic_istream < CharT, Traits > & is,

subtract_with_carry_engine & e ) ;
(2) (since C++11)
1) Writes the textual representation of the current state of e to os with fmtflags set to std:: ios_base :: dec | std:: ios_base :: left and the fill character set to the space character.
After writing, os 's original fmtflags and fill character are restored.
2) Reads a textual representation of engine state from is (denoted as text ) with fmtflags set to std:: ios_base :: dec , and sets the state of e to that state.
After reading, is 's original fmtflags is restored.
  • If text was not previously written using an output stream pr , the behavior is undefined.
  • Otherwise, if any of the following values is false , the behavior is undefined:
  • is. getloc ( ) == pr. getloc ( )
  • std:: is_same < decltype ( is ) :: char_type ,
    decltype ( pr ) :: char_type > :: value
  • std:: is_same < decltype ( is ) :: traits_type ,
    decltype ( pr ) :: traits_type > :: value
  • Otherwise, if text is not a valid textual representation of any state of decltype ( e ) , the state of e is unchanged and is. setstate ( std:: ios_base :: failbit ) is called.
  • Otherwise, given another engine eng of the same type as e . If text was previously written by pr << eng and there is no intervening invocations of e or of eng between pr << eng and is >> e , e == eng is true .

These function templates are not visible to ordinary unqualified or qualified lookup , and can only be found by argument-dependent lookup when decltype ( e ) is an associated class of the arguments.

Parameters

os - output stream to insert the data to
is - input stream to extract the data from
e - pseudo-random number engine

Return value

1) os
2) is

Complexity

1,2) O(r) .

Exceptions

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