ostrstream(); | (1) | |
ostrstream(char* s, int n, std::ios_base::openmode mode = std::ios_base::out); | (2) |
Constructs new output strstream and its underlying std::strstreambuf
.
std::strstreambuf
, which creates a dynamically growing buffer, and initializes the base class with the address of the strstreambuf member.std::strstreambuf
member, which is initialized in one of the two possible ways, both of which write to user-provided fixed-size array: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
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.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):
|
#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!
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 ) |
© cppreference.com
Licensed under the Creative Commons Attribution-ShareAlike Unported License v3.0.
https://en.cppreference.com/w/cpp/io/ostrstream/ostrstream