class template

std::basic_ostringstream

template < class charT,                           // basic_ostringstream::char_type           class traits = char_traits<charT>,     // basic_ostringstream::traits_type           class Alloc = allocator<charT>         // basic_ostringstream::allocator_type           > class basic_ostringstream;

Output string stream

ios_base
basic_ios
basic_ostream
basic_ostringstream

Output stream class to operate on strings.

Objects of this class use a string buffer that contains a sequence of characters. This sequence of characters can be accessed directly as a basic_string object, using member str.

Characters can be inserted into the stream with any operation allowed on output streams.

Apart from the internal string buffer, objects of these classes keep a set of internal fields inherited from ios_base and basic_ios:

	field	member functions	description
Formatting	format flags	`flags` `setf` `unsetf`	A set of internal flags that affect how certain input/output operations are interpreted or generated. See member type `fmtflags`.
	field width	`width`	Width of the next formatted element to insert.
	display precision	`precision`	Decimal precision for the next floating-point value inserted.
	locale	`getloc` `imbue`	The `locale` object used by the function for formatted input/output operations affected by localization properties.
	fill character	`fill`	Character to pad a formatted field up to the field width (`width`).
State	error state	`rdstate` `setstate` `clear`	The current error state of the stream. Individual values may be obtained by calling `good`, `eof`, `fail` and `bad`. See member type `iostate`.
State	exception mask	`exceptions`	The state flags for which a failure exception is thrown. See member type `iostate`.
Other	callback stack	`register_callback`	Stack of pointers to functions that are called when certain events occur.
	extensible arrays	`iword` `pword` `xalloc`	Internal arrays to store objects of type `long` and `void*`.
	tied stream	`tie`	Pointer to output stream that is flushed before each i/o operation on this stream.
	stream buffer	`rdbuf`	Pointer to the associated `basic_streambuf` object, which is charge of all input/output operations.

Template parameters

charT: Character type used by both the stream and the basic_string objects it accepts or generates.
This shall be a non-array POD type.
Aliased as member type basic_ostringstream::char_type.
traits: Character traits class that defines essential properties of the characters used by stream and string objects (see char_traits).
traits::char_type shall be the same as charT.
Aliased as member type basic_ostringstream::traits_type.
Alloc: Type of the allocator object used to define the storage allocation model for the basic_string objects.
By default, the allocator class template is used, which defines the simplest memory allocation model and is value-independent.
Aliased as member type basic_ostringstream::allocator_type.

Template instantiations

ostringstream: Output string stream (class)

wostringstream: Output string stream (wide) (class)

These instantiations are declared in <sstream>.

Member types

The class declares the following member types:

member type	definition	notes
`char_type`	The first template parameter (`charT`)
`traits_type`	The second template parameter (`traits`)	defaults to: `char_traits<charT>`
`allocator_type`	The third template parameter (`Alloc`)	defaults to: `allocator<charT>`
`int_type`	`traits_type::int_type`
`pos_type`	`traits_type::pos_type`	generally, the same as `streampos`
`off_type`	`traits_type::off_type`	generally, the same as `streamoff`

These member types are inherited from its base classes basic_ostream and ios_base:

event: Type to indicate event type (public member type)

event_callback: Event callback function type (public member type)

failure: Base class for stream exceptions (public member class)

fmtflags: Type for stream format flags (public member type)

Init: Initialize standard stream objects (public member class)

iostate: Type for stream state flags (public member type)

openmode: Type for stream opening mode flags (public member type)

seekdir: Type for stream seeking direction flag (public member type)

sentry: Prepare stream for output (public member class)

Public member functions

(constructor): Construct object (public member function)

str: Get/set content (public member function)

operator=: Move assignment (public member function)

swap: Swap internals (public member function)

Public member functions inherited from `basic_ostream`

operator<<: Insert formatted output (public member function)

put: Put character (public member function)

write: Write block of data (public member function)

tellp: Get position in output sequence (public member function)

seekp: Set position in output sequence (public member function)

flush: Flush output stream buffer (public member function)

Public member functions inherited from `basic_ios`

good: Check whether state of stream is good (public member function)

eof: Check whether eofbit is set (public member function)

fail: Check whether failbit or badbit is set (public member function)

bad: Check whether badbit is set (public member function)

operator!: Evaluate stream (not) (public member function)

operator bool: Evaluate stream (public member function)

rdstate: Get error state flags (public member function)

setstate: Set error state flag (public member function)

clear: Set error state flags (public member function)

copyfmt: Copy formatting information (public member function)

fill: Get/set fill character (public member function)

exceptions: Get/set exceptions mask (public member function)

imbue: Imbue locale (public member function)

tie: Get/set tied stream (public member function)

rdbuf: Get/set stream buffer (public member function)

narrow: Narrow character (public member function)

widen: Widen character (public member function)

Public member functions inherited from `ios_base`

flags: Get/set format flags (public member function)

setf: Set specific format flags (public member function)

unsetf: Clear specific format flags (public member function)

precision: Get/Set floating-point decimal precision (public member function)

width: Get/set field width (public member function)

imbue: Imbue locale (public member function)

getloc: Get current locale (public member function)

xalloc: Get new index for extensible array [static] (public static member function)

iword: Get integer element of extensible array (public member function)

pword: Get pointer element of extensible array (public member function)

register_callback: Register event callback function (public member function)

sync_with_stdio: Toggle synchronization with cstdio streams [static] (public static member function)

Non-member function overloads

swap: Swap output string streams (function template)