Standard library header <sstream>

namespace std {
 template<class CharT, class Traits = char_traits<CharT>,
 class Allocator = allocator<CharT>>
 class basic_stringbuf;
 
 using stringbuf = basic_stringbuf<char>;
 using wstringbuf = basic_stringbuf<wchar_t>;
 
 template<class CharT, class Traits = char_traits<CharT>,
 class Allocator = allocator<CharT>>
 class basic_istringstream;
 
 using istringstream = basic_istringstream<char>;
 using wistringstream = basic_istringstream<wchar_t>;
 
 template<class CharT, class Traits = char_traits<CharT>,
 class Allocator = allocator<CharT>>
 class basic_ostringstream;
 using ostringstream = basic_ostringstream<char>;
 using wostringstream = basic_ostringstream<wchar_t>;
 
 template<class CharT, class Traits = char_traits<CharT>,
 class Allocator = allocator<CharT>>
 class basic_stringstream;
 using stringstream = basic_stringstream<char>;
 using wstringstream = basic_stringstream<wchar_t>;
}

namespace std {
 template<class CharT, class Traits = char_traits<CharT>,
 class Allocator = allocator<CharT>>
 class basic_stringbuf : public basic_streambuf<CharT, Traits> {
 public:
 using char_type = CharT;
 using int_type = typename Traits::int_type;
 using pos_type = typename Traits::pos_type;
 using off_type = typename Traits::off_type;
 using traits_type = Traits;
 using allocator_type = Allocator;
 
 // constructors
 basic_stringbuf() : basic_stringbuf(ios_base::in | ios_base::out) {}
 explicit basic_stringbuf(ios_base::openmode which);
 explicit basic_stringbuf(
 const basic_string<CharT, Traits, Allocator>& s,
 ios_base::openmode which = ios_base::in | ios_base::out);
 explicit basic_stringbuf(const Allocator& a)
 : basic_stringbuf(ios_base::in | ios_base::out, a) {}
 basic_stringbuf(ios_base::openmode which, const Allocator& a);
 explicit basic_stringbuf(
 basic_string<CharT, Traits, Allocator>&& s,
 ios_base::openmode which = ios_base::in | ios_base::out);
 template<class SAlloc>
 basic_stringbuf(
 const basic_string<CharT, Traits, SAlloc>& s, const Allocator& a)
 : basic_stringbuf(s, ios_base::in | ios_base::out, a) {}
 template<class SAlloc>
 basic_stringbuf(
 const basic_string<CharT, Traits, SAlloc>& s,
 ios_base::openmode which, const Allocator& a);
 template<class SAlloc>
 explicit basic_stringbuf(
 const basic_string<CharT, Traits, SAlloc>& s,
 ios_base::openmode which = ios_base::in | ios_base::out);
 basic_stringbuf(const basic_stringbuf&) = delete;
 basic_stringbuf(basic_stringbuf&& rhs);
 basic_stringbuf(basic_stringbuf&& rhs, const Allocator& a);
 
 // assign and swap
 basic_stringbuf& operator=(const basic_stringbuf&) = delete;
 basic_stringbuf& operator=(basic_stringbuf&& rhs);
 void swap(basic_stringbuf& rhs) noexcept(see below);
 
 // getters and setters
 allocator_type get_allocator() const noexcept;
 
 basic_string<CharT, Traits, Allocator> str() const &;
 template<class SAlloc>
 basic_string<CharT,Traits,SAlloc> str(const SAlloc& sa) const;
 basic_string<CharT, Traits, Allocator> str() &&;
 basic_string_view<CharT, Traits> view() const noexcept;
 
 void str(const basic_string<CharT, Traits, Allocator>& s);
 template<class SAlloc>
 void str(const basic_string<CharT, Traits, SAlloc>& s);
 void str(basic_string<CharT, Traits, Allocator>&& s);
 
 protected:
 // overridden virtual functions
 int_type underflow() override;
 int_type pbackfail(int_type c = Traits::eof()) override;
 int_type overflow (int_type c = Traits::eof()) override;
 basic_streambuf<CharT, Traits>* setbuf(CharT*, streamsize) override;
 
 pos_type seekoff(off_type off, ios_base::seekdir way,
 ios_base::openmode which
 = ios_base::in | ios_base::out) override;
 pos_type seekpos(pos_type sp,
 ios_base::openmode which
 = ios_base::in | ios_base::out) override;
 
 private:
 ios_base::openmode mode; // exposition only
 basic_string<CharT, Traits, Allocator> buf; // exposition only
 void init_buf_ptrs(); // exposition only
 };
 
 template<class CharT, class Traits, class Allocator>
 void swap(basic_stringbuf<CharT, Traits, Allocator>& x,
 basic_stringbuf<CharT, Traits, Allocator>& y) noexcept(noexcept(x.swap(y)));
}

namespace std {
 template<class CharT, class Traits = char_traits<CharT>,
 class Allocator = allocator<CharT>>
 class basic_istringstream : public basic_istream<CharT, Traits> {
 public:
 using char_type = CharT;
 using int_type = typename Traits::int_type;
 using pos_type = typename Traits::pos_type;
 using off_type = typename Traits::off_type;
 using traits_type = Traits;
 using allocator_type = Allocator;
 
 // constructors
 basic_istringstream() : basic_istringstream(ios_base::in) {}
 explicit basic_istringstream(ios_base::openmode which);
 explicit basic_istringstream(
 const basic_string<CharT, Traits, Allocator>& s,
 ios_base::openmode which = ios_base::in);
 basic_istringstream(ios_base::openmode which, const Allocator& a);
 explicit basic_istringstream(
 basic_string<CharT, Traits, Allocator>&& s,
 ios_base::openmode which = ios_base::in);
 template<class SAlloc>
 basic_istringstream(
 const basic_string<CharT, Traits, SAlloc>& s, const Allocator& a)
 : basic_istringstream(s, ios_base::in, a) {}
 template<class SAlloc>
 basic_istringstream(
 const basic_string<CharT, Traits, SAlloc>& s,
 ios_base::openmode which, const Allocator& a);
 template<class SAlloc>
 explicit basic_istringstream(
 const basic_string<CharT, Traits, SAlloc>& s,
 ios_base::openmode which = ios_base::in);
 basic_istringstream(const basic_istringstream&) = delete;
 basic_istringstream(basic_istringstream&& rhs);
 
 // assign and swap
 basic_istringstream& operator=(const basic_istringstream&) = delete;
 basic_istringstream& operator=(basic_istringstream&& rhs);
 void swap(basic_istringstream& rhs);
 
 // members
 basic_stringbuf<CharT, Traits, Allocator>* rdbuf() const;
 basic_string<CharT, Traits, Allocator> str() const &;
 template<class SAlloc>
 basic_string<CharT,Traits,SAlloc> str(const SAlloc& sa) const;
 basic_string<CharT, Traits, Allocator> str() &&;
 basic_string_view<CharT, Traits> view() const noexcept;
 
 void str(const basic_string<CharT, Traits, Allocator>& s);
 template<class SAlloc>
 void str(const basic_string<CharT, Traits, SAlloc>& s);
 void str(basic_string<CharT, Traits, Allocator>&& s);
 
 private:
 basic_stringbuf<CharT, Traits, Allocator> sb; // exposition only
 };
 
 template<class CharT, class Traits, class Allocator>
 void swap(basic_istringstream<CharT, Traits, Allocator>& x,
 basic_istringstream<CharT, Traits, Allocator>& y);
}

namespace std {
 template<class CharT, class Traits = char_traits<CharT>,
 class Allocator = allocator<CharT>>
 class basic_ostringstream : public basic_ostream<CharT, Traits> {
 public:
 using char_type = CharT;
 using int_type = typename Traits::int_type;
 using pos_type = typename Traits::pos_type;
 using off_type = typename Traits::off_type;
 using traits_type = Traits;
 using allocator_type = Allocator;
 
 // constructors
 basic_ostringstream() : basic_ostringstream(ios_base::out) {}
 explicit basic_ostringstream(ios_base::openmode which);
 explicit basic_ostringstream(
 const basic_string<CharT, Traits, Allocator>& s,
 ios_base::openmode which = ios_base::out);
 basic_ostringstream(ios_base::openmode which, const Allocator& a);
 explicit basic_ostringstream(
 basic_string<CharT, Traits, Allocator>&& s,
 ios_base::openmode which = ios_base::out);
 template<class SAlloc>
 basic_ostringstream(
 const basic_string<CharT, Traits, SAlloc>& s, const Allocator& a)
 : basic_ostringstream(s, ios_base::out, a) {}
 template<class SAlloc>
 basic_ostringstream(
 const basic_string<CharT, Traits, SAlloc>& s,
 ios_base::openmode which, const Allocator& a);
 template<class SAlloc>
 explicit basic_ostringstream(
 const basic_string<CharT, Traits, SAlloc>& s,
 ios_base::openmode which = ios_base::out);
 basic_ostringstream(const basic_ostringstream&) = delete;
 basic_ostringstream(basic_ostringstream&& rhs);
 
 // assign and swap
 basic_ostringstream& operator=(const basic_ostringstream&) = delete;
 basic_ostringstream& operator=(basic_ostringstream&& rhs);
 void swap(basic_ostringstream& rhs);
 
 // members
 basic_stringbuf<CharT, Traits, Allocator>* rdbuf() const;
 
 basic_string<CharT, Traits, Allocator> str() const &;
 template<class SAlloc>
 basic_string<CharT,Traits,SAlloc> str(const SAlloc& sa) const;
 basic_string<CharT, Traits, Allocator> str() &&;
 basic_string_view<CharT, Traits> view() const noexcept;
 
 void str(const basic_string<CharT, Traits, Allocator>& s);
 template<class SAlloc>
 void str(const basic_string<CharT, Traits, SAlloc>& s);
 void str(basic_string<CharT, Traits, Allocator>&& s);
 
 private:
 basic_stringbuf<CharT, Traits, Allocator> sb; // exposition only
 };
 
 template<class CharT, class Traits, class Allocator>
 void swap(basic_ostringstream<CharT, Traits, Allocator>& x,
 basic_ostringstream<CharT, Traits, Allocator>& y);
}

namespace std {
 template<class CharT, class Traits = char_traits<CharT>,
 class Allocator = allocator<CharT>>
 class basic_stringstream : public basic_iostream<CharT, Traits> {
 public:
 using char_type = CharT;
 using int_type = typename Traits::int_type;
 using pos_type = typename Traits::pos_type;
 using off_type = typename Traits::off_type;
 using traits_type = Traits;
 using allocator_type = Allocator;
 
 // constructors
 basic_stringstream() : basic_stringstream(ios_base::out | ios_base::in) {}
 explicit basic_stringstream(ios_base::openmode which);
 explicit basic_stringstream(
 const basic_string<CharT, Traits, Allocator>& s,
 ios_base::openmode which = ios_base::out | ios_base::in);
 basic_stringstream(ios_base::openmode which, const Allocator& a);
 explicit basic_stringstream(
 basic_string<CharT, Traits, Allocator>&& s,
 ios_base::openmode which = ios_base::out | ios_base::in);
 template<class SAlloc>
 basic_stringstream(
 const basic_string<CharT, Traits, SAlloc>& s, const Allocator& a)
 : basic_stringstream(s, ios_base::out | ios_base::in, a) {}
 template<class SAlloc>
 basic_stringstream(
 const basic_string<CharT, Traits, SAlloc>& s,
 ios_base::openmode which, const Allocator& a);
 template<class SAlloc>
 explicit basic_stringstream(
 const basic_string<CharT, Traits, SAlloc>& s,
 ios_base::openmode which = ios_base::out | ios_base::in);
 basic_stringstream(const basic_stringstream&) = delete;
 basic_stringstream(basic_stringstream&& rhs);
 
 // assign and swap
 basic_stringstream& operator=(const basic_stringstream&) = delete;
 basic_stringstream& operator=(basic_stringstream&& rhs);
 void swap(basic_stringstream& rhs);
 
 // members
 basic_stringbuf<CharT, Traits, Allocator>* rdbuf() const;
 
 basic_string<CharT, Traits, Allocator> str() const &;
 template<class SAlloc>
 basic_string<CharT,Traits,SAlloc> str(const SAlloc& sa) const;
 basic_string<CharT, Traits, Allocator> str() &&;
 basic_string_view<CharT, Traits> view() const noexcept;
 
 void str(const basic_string<CharT, Traits, Allocator>& s);
 template<class SAlloc>
 void str(const basic_string<CharT, Traits, SAlloc>& s);
 void str(basic_string<CharT, Traits, Allocator>&& s);
 
 private:
 basic_stringbuf<CharT, Traits> sb; // exposition only
 };
 
 template<class CharT, class Traits, class Allocator>
 void swap(basic_stringstream<CharT, Traits, Allocator>& x,
 basic_stringstream<CharT, Traits, Allocator>& y);
}