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std::basic_...gstream::str(3)  C++ Standard Libary std::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. Equiv-
     alent to
	return rdbuf()->str(a);.
	3) Returns a string move-constructed from the underlying string. Equiva-
     lent to
	return std::move(*rdbuf()).str();.
	4,5)  Replaces	the contents of the underlying string. Equivalent to rd-
     buf()->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_convert-
     ible_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 object
     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		Feature
	__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_stringbuf<CharT,Traits,Allo-
     cator>)

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