message: Add argc/argv inputs to main function
diff: using namespace std;
  -int main(/*argv, argc*/) {
  -
  - cout << "Hello World!" << endl;
  +int main(int argc, char **argv) {
  + if (argc != 2) {
  + // insert error msg
  + return 1;
  + }
  - char *ex;
  - Parser parser(ex);
  + Parser parser(argv[1]);
  Runner runner(&parser);
  + // execute runner
  return runner.exec();
  }
  