Question

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)?

Answer 1

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