std::ostrstream:: ostrstream
From cppreference.com
<
cpp
|
io
|
ostrstream
|
ostrstream
(
)
;
|
(1) |
(deprecated in C++98)
(removed in C++26) |
|
ostrstream
(
char
*
s,
int
n,
std::
ios_base
::
openmode
mode
=
std::
ios_base
::
out
)
;
|
(2) |
(deprecated in C++98)
(removed in C++26) |
Constructs new output strstream and its underlying std::strstreambuf .
1)
Default-constructs the underlying
std::strstreambuf
, which creates a dynamically growing buffer, and initializes the base class with the address of the
strstreambuf
member.
2)
Initialized the base class with the address of the underlying
std::strstreambuf
member, which is initialized in one of the two possible ways, both of which write to user-provided fixed-size array:
a)
if the
app
bit is not set in
mode
, constructs the buffer by calling
strstreambuf
(
s, n, s
)
. The behavior is undefined if there are less than
n
elements in the array whose first element is pointed to by
s
b)
if the
app
bit is set in
mode
, constructs the buffer by calling
strstreambuf
(
s, n, s
+
std::
strlen
(
s
)
)
. The behavior is undefined if there are less than
n
elements in the array whose first element is pointed to by
s
or if the array does not contain a valid null-terminated character sequence.
Parameters
| s | - | char array to use as the output buffer | ||||||||||||||||
| n | - | size of the array to be used as the output buffer | ||||||||||||||||
| mode | - |
specifies stream open mode. It is a bitmask type, the following constants are defined (although only
app
is used):
|
Example
Run this code
#include <iostream> #include <strstream> int main() { std::ostrstream s1; // dynamic buffer s1 << 1 << ' ' << 3.14 << " example\n" << std::ends; std::cout << s1.str(); s1.freeze(false); char arr[15] = "Hello"; std::ostrstream s2(arr, sizeof arr, std::ios_base::app); s2 << ", world!" << std::ends; std::cout << s2.str() << '\n'; std::cout << arr << '\n'; // streams use the provided arrays }
Output:
1 3.14 example Hello, world! Hello, world!
See also
constructs a
strstreambuf
object
(public member function of
std::strstreambuf
)
|
|
constructs an
istrstream
object, optionally allocating the buffer
(public member function of
std::istrstream
)
|
|
constructs a
strstream
object, optionally allocating the buffer
(public member function of
std::strstream
)
|