How copy from one stringstream object to another in C++?

问题

I have std::stringstream object ss1. Now, I would like to create another copy from this one.

I try this:

std::stringstream ss2 = ss1;

or:

std::stringstream ss2(ss1)

neither works

The error message is like this:

std::ios::basic_ios(const std::ios &) is not accessible from bsl::basic_stringstream, bsl::allocator>::basic_stringstream(const bsl::basic_stringstream, bsl::allocator>&).

回答1:

Indeed, streams are non-copyable (though they are movable).

Depending on your usage, the following works quite well:

#include <iostream>
#include <sstream>

int main()
{
    std::stringstream ss1;
    ss1 << "some " << 123 << " stuff" << std::flush;

    std::stringstream ss2;
    ss2 << ss1.rdbuf(); // copy everything inside ss1's buffer to ss2's buffer

    std::cout << ss1.str() << std::endl;
    std::cout << ss2.str() << std::endl;
}

Output:

some 123 stuff
some 123 stuff

回答2:

As std::stringstream does not provide a copy constructor, you have to build it from the std::string ss1outputs:

std::stringstream ss2(ss1.str());

来源：https://stackoverflow.com/questions/3442520/how-copy-from-one-stringstream-object-to-another-in-c