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std::basic_...gstream::str(3) C++ Standard Libarystd::basic_...gstream::str(3)

NAME
       std::basic_istringstream::str - std::basic_istringstream::str

Synopsis
	  std::basic_string<CharT,    Traits,	 Allocator>    str()	const;
       (until C++20)
	  std::basic_string<CharT,   Traits,	Allocator>    str()    const&;
       (since C++20)
	  template< class SAlloc >
	  std::basic_string<CharT,   Traits,  SAlloc>  str(  const  SAlloc&  a
       (2) (since C++20)
	  ) const;
	  std::basic_string<CharT,    Traits,	  Allocator>	 str()	   &&;
       (3) (since C++20)
	  void	str(  const std::basic_string<CharT, Traits, Allocator>& s (1)
       (4)
	  );
	  template<		  class		       SAlloc		     >
       (5) (since C++20)
	  void str( const std::basic_string<CharT, Traits, SAlloc>& s );
	  void	 str(	std::basic_string<CharT,  Traits,  Allocator>&&	 s  );
       (6) (since C++20)
	  template<		class		  StringViewLike	     >
       (7) (since C++26)
	  void str( const StringViewLike& t );

	  Manages the contents of the underlying string	object.

	  1) Returns a copy of the underlying string. Equivalent to return rd-
       buf()->str();.
	  2)  Returns  a  copy of the underlying string, using a as allocator.
       Equivalent to
	  return rdbuf()->str(a);.
	  3) Returns a string move-constructed	from  the  underlying  string.
       Equivalent to
	  return std::move(*rdbuf()).str();.
	  4,5)	Replaces  the contents of the underlying string. Equivalent to
       rdbuf()->str(s);.
	  6) Replaces the contents of the underlying string. Equivalent	to
	  rdbuf()->str(std::move(s));.
	  7) Replaces the contents of the underlying string. Equivalent	to rd-
       buf()->str(t);.
	  This overload	participates in	overload resolution  only  if  is_con-
       vertible_v<const	T&,
	  basic_string_view<charT, traits>> is true.

Parameters
	  s - new contents of the underlying string
	  t  - an object (convertible to std::basic_string_view) to use	as the
       new contents of
	      the underlying string
	  a - allocator	used to	construct the returned string

Return value
	  1,2) A copy of the underlying	string object.
	  3) A string move-constructed from the	underlying string object.
	  4-7) (none)

Notes
	  The copy of the underlying string returned by	str is a temporary ob-
       ject that will be
	  destructed at	the end	of the expression, so directly calling c_str()
       on the result
	  of str() (for	example	in auto	*ptr = out.str().c_str();) results  in
       a dangling
	  pointer.

		  Feature-test macro	      Value    Std		  Fea-
       ture
	  __cpp_lib_sstream_from_string_view   202306L	 (C++26)   Interfacing
       std::stringstreams
							     with
       std::string_view, (7)

Example
       // Run this code

	#include <iostream>
	#include <sstream>

	int main()
	{
	    int	n;

	    std::istringstream in; // could also use in("1 2")
	    in.str("1 2");
	    in >> n;
	    std::cout << "After	reading	the first int from \"1 2\", the	int is
       "
		      << n << ", str() = \"" <<	in.str() << "\"\n";

	    std::ostringstream out("1 2");
	    out	<< 3;
	    std::cout << "After	writing	the int	'3' to output stream \"1 2\""
		      << ", str() = \""	<< out.str() <<	"\"\n";

	    std::ostringstream ate("1 2", std::ios_base::ate);
	    ate	<< 3;
	    std::cout << "After	writing	the int	'3' to append stream \"1 2\""
		      << ", str() = \""	<< ate.str() <<	"\"\n";
	}

Output:
	After reading the first	int from "1 2",	the int	is 1, str() = "1 2"
	After writing the int '3' to output stream "1 2", str()	= "3 2"
	After writing the int '3' to append stream "1 2", str()	= "1 23"

See also
	  rdbuf	returns	the underlying raw string device object
		(public	member function)
		replaces or obtains a copy of the associated character string
	  str	   (public    member	function     of	    std::basic_string-
       buf<CharT,Traits,Allocator>)

http://cppreference.com		  2024.06.10	 std::basic_...gstream::str(3)

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