[c++] C++ compile error: has initializer but incomplete type

I am coding in Eclipse and have something like the following:

#include <ftream>
#include <iostream>

void read_file(){
    char buffer[1025];
    std::istringstream iss(buffer);
}

However, when I try to build, I get the following error: variable 'std::istringstream iss' has initializer but incomplete type

Any quick thoughts? I have googled around and it seems like most people with this problem simply did not include the right header files which I believe I am doing correctly.

` Please include either of these:

`#include<sstream>`

using std::istringstream;