std::ostringstream不提供公共接口来访问其内存中缓冲区，除非它非便携式地支持pubsetbuf(但即使那样，您的缓冲区也是固定大小的) ，请参见 cppreference示例)

std::ostringstream offers no public interface to access its in-memory buffer unless it non-portably supports pubsetbuf (but even then your buffer is fixed-size, see cppreference example)

如果要折磨某些字符串流，可以使用受保护的接口访问缓冲区:

If you want to torture some string streams, you could access the buffer using the protected interface:

#include <iostream>
#include <sstream>
#include <vector>

struct my_stringbuf : std::stringbuf {
    const char* my_str() const { return pbase(); } // pptr might be useful too
};

int main()
{
    std::vector<float> v = {1.1, -3.4, 1/7.0};
    my_stringbuf buf;
    std::ostream ss(&buf);
    for(unsigned int i=0; i < v.size(); ++i)
        ss << v[i] << ' ';
    ss << std::ends;
    std::cout << buf.my_str() << '\n';
}

std::ostrstream提供了直接访问自动调整大小的输出流缓冲区的标准C ++方法，在c ++ 98中已弃用，但在标准c ++ 14中仍在计数.

The standard C++ way of directly accessing an auto-resizing output stream buffer is offered by std::ostrstream, deprecated in C++98, but still standard C++14 and counting.

#include <iostream>
#include <strstream>
#include <vector>

int main()
{
    std::vector<float> v = {1.1, -3.4, 1/7.0};
    std::ostrstream ss;
    for(unsigned int i=0; i < v.size(); ++i)
        ss << v[i] << ' ';
    ss << std::ends;
    const char* buffer = ss.str(); // direct access!
    std::cout << buffer << '\n';
    ss.freeze(false); // abomination
}

但是，我认为最干净(也是最快)的解决方案是

However, I think the cleanest (and the fastest) solution is boost.karma

#include <iostream>
#include <string>
#include <vector>
#include <boost/spirit/include/karma.hpp>
namespace karma = boost::spirit::karma;
int main()
{
    std::vector<float> v = {1.1, -3.4, 1/7.0};
    std::string s;
    karma::generate(back_inserter(s), karma::double_ % ' ', v);
    std::cout << s << '\n'; // here's your string
}