Another way to do it in C++ is:

  #include <iterator>
  #include<vector>
  #include<algorithm>
  #include<fstream>

  using namespace std; // Bad but shorter!

  int main(int argc, char** argv) {
      ifstream infile(argv[1]);
      ofstream outfile(argv[2]);
      ifstream_iterator<string> start(infile), end;
      vector<string> lines(start, end);
      sort(lines.begin(), lines.end());
      copy(lines.begin(), lines.end(), ostream_iterator<char>(outfile, "\n"));
  }