Write a program that reads in a file 
(name given by user) that contains points 
in ordered pair notation, and writes the 
same points to a file (name also given by 
user) in gnuplot notation, i.e. one point 
per line, each point given by x-coordinate 
tab ('\t') y-coordinate.
#include <iostream>
#include <fstream>
#include <string>
using namespace std;

int main()
  // Read input and output file names
  string inname, outname;
  cout << "Input file name: ";
  cin >> inname;
  cout << "Output file name: ";
  cin >> outname;

  // Open up input and output files
  ifstream fin(inname.c_str());
  ofstream fout(outname.c_str());

  // loop over each point & convert
  char c;
  double x, y;
  while(fin >> c >> x >> c >> y >> c)
    fout << x << '\t' << y << endl;

  return 0;