expected token How can I fix that problem?

When I add this to my code:

while (std::getline(file, str, '\n'))
{
   istringstream iss(str);
   vector<string> line;
   copy(istream_iterator<string>(iss), istream_iterator<string>(), back_inserter(line));
   counter = 0;

In the part of

copy(istream_iterator<string>(iss), istream_iterator<string>(),
back_inserter(line));

I get the error:

  

error: expected primary-expression before ')' token

How can I solve this problem?