I have a vector<char>
of data which I want to write into std::stringstream
.
I tried:
my_ss.write(vector.data(), vector.size());
...but it seems to put nothing into my_ss
which I declared as follows:
std::stringstream my_ss( std::stringstream::binary);
Why write is not working (app does not crash and compiles with 0 errors, 0 warnings)?
For the "how do I do it" you can use a std::ostream_iterator
:
std::copy(vector.begin(), vector.end(), std::ostream_iterator<char>(my_ss));
Complete example:
#include <iterator>
#include <sstream>
#include <vector>
#include <iostream>
#include <algorithm>
int main() {
std::vector<char> vector(60, 'a');
std::ostringstream my_ss;
std::copy(vector.begin(), vector.end(), std::ostream_iterator<char>(my_ss));
std::cout << my_ss.str() << std::endl;
}
You could also just use that to construct a string
directly, without going via a stringstream
at all:
std::string str(vector.begin(), vector.end()); // skip all of the copy and stringstream
Though you haven't given any code, it sounds like you probably just wrote:
std::stringstream my_ss (std::stringstream::binary);
If you wish to write to a stringstream you need to combine the flag std::stringstream::out
in the constructor. If I'm right, then you would see things working fine if you changed this to:
std::stringstream my_ss (std::stringstream::out | std::stringstream::binary);
(Obviously if you wish to read from that stringstream you need to add std::stringstream::in
)
UPDATE Now that you've given your code...yup, this is your specific problem. Note @awoodland's point about the fact that you can just construct a string from a vector of chars instead (if that's the only thing you were planning on doing with this stream.)
The default parameter for the mode of stringbuf in stringstream is out|in.
explicit basic_stringstream(ios_base::openmode _Mode =
ios_base::in | ios_base::out)
: _Mybase(&_Stringbuffer),
_Stringbuffer(_Mode)
{ // construct empty character buffer
}
You need to add stringstream::out if you pass something explicitly like stringstream:binary
Or just use std::ostringstream
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