how to write ostringstream directly to cout
c++
Solution
Not if you're using `std::ostringstream`. The underlying buffer for this cannot be read from (hence the `o` in `ostringstream`), so you have to rely on the implementation to do it for you, via `str()`.
However, if you use `std::stringstream` (note the lack of `o`), then the underlying buffer is readable, and `basic_ostream`'s have a special overload forreading from buffers:
#include <iostream>
#include <sstream>
int main()
{
std::stringstream ss1;
ss1 << "some " << 111605 << " stuff" << std::flush;
std::cout << ss1.rdbuf() << std::endl;
std::cout << ss1.str() << std::endl;
}
Output:
some 111605 stuff some 111605 stuff
(Example derived from here.)
This copies directly from the underlying buffer, without an intermediate copy.
Problem
If I have an `std::ostringstream` object called `oss`, I understand I can do `std::cout << oss.str()` to print out the string. But doing `oss.str()` would result in the returned string being copied. Is there a way to print directly the underlying `streambuf`? Thanks in advance!