Difference between revisions of "cpp/io/basic ostringstream"

Revision as of 09:00, 24 August 2023

Defined in header `<sstream>`
template< class CharT, class Traits = std::char_traits<CharT>, class Allocator = std::allocator<CharT> > class basic_ostringstream : public basic_ostream<CharT, Traits>;

The class template std::basic_ostringstream implements output operations on string based streams. It effectively stores an instance of std::basic_string and performs output operations to it.

At the low level, the class essentially wraps a raw string device implementation of std::basic_stringbuf into a higher-level interface of std::basic_ostream. The complete interface to unique std::basic_stringbuf members is provided.

Inheritance diagram

Several typedefs for common character types are provided:

Defined in header `<sstream>`
Type	Definition
`std::ostringstream`	std::basic_ostringstream<char>
`std::wostringstream`	std::basic_ostringstream<wchar_t>

Member types

Member type	Definition
`char_type`	`CharT`[edit]
`traits_type`	`Traits`; the program is ill-formed if `Traits::char_type` is not `CharT`.[edit]
`int_type`	`Traits::int_type`[edit]
`pos_type`	`Traits::pos_type`[edit]
`off_type`	`Traits::off_type`[edit]
`allocator_type`	`Allocator`[edit]

Member functions

(constructor)	constructs the string stream (public member function) [edit]
operator= (C++11)	moves the string stream (public member function) [edit]
swap (C++11)	swaps two string streams (public member function) [edit]
rdbuf	returns the underlying raw string device object (public member function) [edit]
String operations
str	gets or sets the contents of underlying string device object (public member function) [edit]
view (C++20)	obtains a view over the contents of underlying string device object (public member function) [edit]

Non-member functions

std::swap(std::basic_ostringstream)

(C++11)

specializes the std::swap algorithm
(function template) [edit]

Inherited from std::basic_ostream

Member functions

Formatted output
operator<<	inserts formatted data (public member function of `std::basic_ostream<CharT,Traits>`) [edit]
Unformatted output
put	inserts a character (public member function of `std::basic_ostream<CharT,Traits>`) [edit]
write	inserts blocks of characters (public member function of `std::basic_ostream<CharT,Traits>`) [edit]
Positioning
tellp	returns the output position indicator (public member function of `std::basic_ostream<CharT,Traits>`) [edit]
seekp	sets the output position indicator (public member function of `std::basic_ostream<CharT,Traits>`) [edit]
Miscellaneous
flush	synchronizes with the underlying storage device (public member function of `std::basic_ostream<CharT,Traits>`) [edit]

Member classes

sentry

implements basic logic for preparation of the stream for output operations
(public member class of std::basic_ostream<CharT,Traits>) [edit]

Inherited from std::basic_ios

Member types

Member type	Definition
`char_type`	`CharT`
`traits_type`	`Traits`
`int_type`	`Traits::int_type`
`pos_type`	`Traits::pos_type`
`off_type`	`Traits::off_type`

Member functions

State functions
good	checks if no error has occurred i.e. I/O operations are available (public member function of `std::basic_ios<CharT,Traits>`) [edit]
eof	checks if end-of-file has been reached (public member function of `std::basic_ios<CharT,Traits>`) [edit]
fail	checks if an error has occurred (public member function of `std::basic_ios<CharT,Traits>`) [edit]
bad	checks if a non-recoverable error has occurred (public member function of `std::basic_ios<CharT,Traits>`) [edit]
operator!	checks if an error has occurred (synonym of fail()) (public member function of `std::basic_ios<CharT,Traits>`) [edit]
operator bool	checks if no error has occurred (synonym of `!`fail()) (public member function of `std::basic_ios<CharT,Traits>`) [edit]
rdstate	returns state flags (public member function of `std::basic_ios<CharT,Traits>`) [edit]
setstate	sets state flags (public member function of `std::basic_ios<CharT,Traits>`) [edit]
clear	modifies state flags (public member function of `std::basic_ios<CharT,Traits>`) [edit]
Formatting
copyfmt	copies formatting information (public member function of `std::basic_ios<CharT,Traits>`) [edit]
fill	manages the fill character (public member function of `std::basic_ios<CharT,Traits>`) [edit]
Miscellaneous
exceptions	manages exception mask (public member function of `std::basic_ios<CharT,Traits>`) [edit]
imbue	sets the locale (public member function of `std::basic_ios<CharT,Traits>`) [edit]
rdbuf	manages associated stream buffer (public member function of `std::basic_ios<CharT,Traits>`) [edit]
tie	manages tied stream (public member function of `std::basic_ios<CharT,Traits>`) [edit]
narrow	narrows characters (public member function of `std::basic_ios<CharT,Traits>`) [edit]
widen	widens characters (public member function of `std::basic_ios<CharT,Traits>`) [edit]

Inherited from std::ios_base

Member functions

Formatting
flags	manages format flags (public member function of `std::ios_base`) [edit]
setf	sets specific format flag (public member function of `std::ios_base`) [edit]
unsetf	clears specific format flag (public member function of `std::ios_base`) [edit]
precision	manages decimal precision of floating point operations (public member function of `std::ios_base`) [edit]
width	manages field width (public member function of `std::ios_base`) [edit]
Locales
imbue	sets locale (public member function of `std::ios_base`) [edit]
getloc	returns current locale (public member function of `std::ios_base`) [edit]
Internal extensible array
xalloc [static]	returns a program-wide unique integer that is safe to use as index to `pword()` and `iword()` (public static member function of `std::ios_base`) [edit]
iword	resizes the private storage if necessary and access to the long element at the given index (public member function of `std::ios_base`) [edit]
pword	resizes the private storage if necessary and access to the void* element at the given index (public member function of `std::ios_base`) [edit]
Miscellaneous
register_callback	registers event callback function (public member function of `std::ios_base`) [edit]
sync_with_stdio [static]	sets whether C++ and C I/O libraries are interoperable (public static member function of `std::ios_base`) [edit]
Member classes
failure	stream exception (public member class of `std::ios_base`) [edit]
Init	initializes standard stream objects (public member class of `std::ios_base`) [edit]

Member types and constants

Type Explanation

openmode

stream open mode type

The following constants are also defined:

Constant	Explanation[edit]
`app`	seek to the end of stream before each write[edit]
`binary`	open in binary mode[edit]
`in`	open for reading[edit]
`out`	open for writing[edit]
`trunc`	discard the contents of the stream when opening[edit]
`ate`	seek to the end of stream immediately after open[edit]
`noreplace` (C++23)	open in exclusive mode[edit]

(typedef) [edit]

fmtflags

formatting flags type

The following constants are also defined:

Constant	Explanation[edit]
`dec`	use decimal base for integer I/O: see std::dec[edit]
`oct`	use octal base for integer I/O: see std::oct[edit]
`hex`	use hexadecimal base for integer I/O: see std::hex[edit]
`basefield`	dec \| oct \| hex. Useful for masking operations[edit]
`left`	left adjustment (adds fill characters to the right): see std::left[edit]
`right`	right adjustment (adds fill characters to the left): see std::right[edit]
`internal`	internal adjustment (adds fill characters to the internal designated point): see std::internal[edit]
`adjustfield`	left \| right \| internal. Useful for masking operations[edit]
`scientific`	generate floating point types using scientific notation, or hex notation if combined with fixed: see std::scientific[edit]
`fixed`	generate floating point types using fixed notation, or hex notation if combined with scientific: see std::fixed[edit]
`floatfield`	scientific \| fixed. Useful for masking operations[edit]
`boolalpha`	insert and extract bool type in alphanumeric format: see std::boolalpha[edit]
`showbase`	generate a prefix indicating the numeric base for integer output, require the currency indicator in monetary I/O: see std::showbase[edit]
`showpoint`	generate a decimal-point character unconditionally for floating-point number output: see std::showpoint[edit]
`showpos`	generate a + character for non-negative numeric output: see std::showpos[edit]
`skipws`	skip leading whitespace before certain input operations: see std::skipws[edit]
`unitbuf`	flush the output after each output operation: see std::unitbuf[edit]
`uppercase`	replace certain lowercase letters with their uppercase equivalents in certain output operations: see std::uppercase[edit]

(typedef) [edit]

iostate

state of the stream type

The following constants are also defined:

Constant	Explanation[edit]
`goodbit`	no error[edit]
`badbit`	irrecoverable stream error[edit]
`failbit`	input/output operation failed (formatting or extraction error)[edit]
`eofbit`	associated input sequence has reached end-of-file[edit]

(typedef) [edit]

seekdir

seeking direction type

The following constants are also defined:

Constant	Explanation[edit]
`beg`	the beginning of a stream[edit]
`end`	the ending of a stream[edit]
`cur`	the current position of stream position indicator[edit]

(typedef) [edit]

event

specifies event type
(enum) [edit]

event_callback

callback function type
(typedef) [edit]

@@ Line 2: / Line 2: @@
 {{cpp/io/basic_ostringstream/navbar}}
 {{ddcl|header=sstream|1=
 template<
      class CharT,
      class Traits = std::char_traits<CharT>,
      class Allocator = std::allocator<CharT>
-> class basic_ostringstream : public basic_ostream<CharT, Traits>;
+> class basic_ostringstream
+    : public basic_ostream<CharT, Traits>;
 }}
@@ Line 19: / Line 20: @@
 ===Member types===
 {{dsc begin}}
-{{dsc hitem | Member type | Definition}}
+{{dsc hitem|Member type|Definition}}
-{{dsc inc | cpp/io/dsc char_type}}
+{{dsc inc|cpp/io/dsc char_type}}
-{{dsc inc | cpp/io/dsc traits_type}}
+{{dsc inc|cpp/io/dsc traits_type}}
-{{dsc inc | cpp/io/dsc int_type}}
+{{dsc inc|cpp/io/dsc int_type}}
-{{dsc inc | cpp/io/dsc pos_type}}
+{{dsc inc|cpp/io/dsc pos_type}}
-{{dsc inc | cpp/io/dsc off_type}}
+{{dsc inc|cpp/io/dsc off_type}}
-{{dsc inc | cpp/io/dsc allocator_type}}
+{{dsc inc|cpp/io/dsc allocator_type}}
 {{dsc end}}
 ===Member functions===
 {{dsc begin}}
-{{dsc inc | cpp/io/basic_stringstream/dsc constructor | basic_ostringstream}}
+{{dsc inc|cpp/io/basic_stringstream/dsc constructor|basic_ostringstream}}
-{{dsc inc | cpp/io/basic_stringstream/dsc operator{{=}} | basic_ostringstream}}
+{{dsc inc|cpp/io/basic_stringstream/dsc operator{{=}}|basic_ostringstream}}
-{{dsc inc | cpp/io/basic_stringstream/dsc swap | basic_ostringstream}}
+{{dsc inc|cpp/io/basic_stringstream/dsc swap|basic_ostringstream}}
-{{dsc inc | cpp/io/basic_stringstream/dsc rdbuf | basic_ostringstream}}
+{{dsc inc|cpp/io/basic_stringstream/dsc rdbuf|basic_ostringstream}}
-{{dsc h2 | String operations }}
+{{dsc h2|String operations}}
-{{dsc inc | cpp/io/basic_stringstream/dsc str | basic_ostringstream}}
+{{dsc inc|cpp/io/basic_stringstream/dsc str|basic_ostringstream}}
-{{dsc inc | cpp/io/basic_stringstream/dsc view | basic_ostringstream}}
+{{dsc inc|cpp/io/basic_stringstream/dsc view|basic_ostringstream}}
 {{dsc end}}
 ===Non-member functions===
 {{dsc begin}}
-{{dsc inc | cpp/io/basic_stringstream/dsc swap2 | basic_ostringstream}}
+{{dsc inc|cpp/io/basic_stringstream/dsc swap2|basic_ostringstream}}
 {{dsc end}}

Compiler support
Freestanding and hosted
Language
Standard library
Standard library headers
Named requirements
Feature test macros (C++20)
Language support library
Concepts library (C++20)
Metaprogramming library (C++11)
Diagnostics library
General utilities library
Strings library
Containers library
Iterators library
Ranges library (C++20)
Algorithms library
Numerics library
Localizations library
Input/output library
Filesystem library (C++17)
Regular expressions library (C++11)
Concurrency support library (C++11)
Execution support library (C++26)
Technical specifications
Symbols index
External libraries

I/O manipulators
Print functions (C++23)
C-style I/O
Buffers
basic_streambuf
basic_filebuf
basic_stringbuf
basic_spanbuf (C++23)
strstreambuf (C++98/26*)
basic_syncbuf (C++20)
Streams
Abstractions
ios_base
basic_ios
basic_istream
basic_ostream
basic_iostream
File I/O
basic_ifstream
basic_ofstream
basic_fstream
String I/O
basic_istringstream
basic_ostringstream
basic_stringstream
Array I/O
basic_ispanstream (C++23)
basic_ospanstream (C++23)
basic_spanstream (C++23)
istrstream (C++98/26*)
ostrstream (C++98/26*)
strstream (C++98/26*)
Synchronized Output
basic_osyncstream (C++20)
Types
streamoff
streamsize
fpos
Error category interface
iostream_category (C++11)
io_errc (C++11)

Member functions
basic_ostringstream::basic_ostringstream
basic_ostringstream::operator=
basic_ostringstream::swap (C++11)
basic_ostringstream::rdbuf
String operations
basic_ostringstream::str
basic_ostringstream::view (C++20)
Non-member functions
swap(std::basic_ostringstream) (C++11)

cppreference.com

Namespaces

Variants

Views

Actions

Difference between revisions of "cpp/io/basic ostringstream"

Revision as of 09:00, 24 August 2023

Contents

Member types

Member functions

String operations

Non-member functions

Inherited from std::basic_ostream

Member functions

Formatted output

Unformatted output

Positioning

Miscellaneous

Member classes

Inherited from std::basic_ios

Member types

Member functions

State functions

Formatting

Miscellaneous

Inherited from std::ios_base

Member functions

Formatting

Locales

Internal extensible array

Miscellaneous

Member classes

Member types and constants

Navigation

Toolbox