//
// This is example code from Chapter 10.4 "Opening a file" of
// "Programming -- Principles and Practice Using C++" by Bjarne Stroustrup
//

#include <iostream>
#include <fstream>
#include <string>
#include "std_lib_facilities.h"

using namespace std;

//------------------------------------------------------------------------------

struct Point
{
   int x;
   int y;

   friend istream& operator>>(istream& ist, Point& p)
   {
      char a,b,c;

      if ((ist >> a >> p.x >> b >> p.y >> c) && !(a == '(' && b == ',' && c == ')'))
	 throw runtime_error("Invalid format");

      return ist;
   }

   friend ostream& operator<<(ostream& ost, const Point& p)
   {
      return ost << '(' << p.x << ',' << p.y << ')' << endl;
   }
};

//------------------------------------------------------------------------------

int main()
   try
      {
         cout << "Please enter input file name: ";
         string name;
         cin >> name;
         ifstream ist{name};   // ist is an input stream for the file named name
         if (!ist) error("can't open input file ",name);

         vector<Point> points;
         Point p;
         while (ist>>p) points.push_back(p);
      }
   catch (exception& e) {
      cerr << "error: " << e.what() << '\n'; 
      return 1;
   }
   catch (...) {
      cerr << "Oops: unknown exception!\n"; 
      return 2;
   }

//------------------------------------------------------------------------------