// A program to write to a file, which can be opened in a spreadsheet
#include <cstdlib>
#include <fstream>
#include <iostream>

int main(int argc, char* argv[])
{
  // open up a file stream to write data
  std::ofstream output;
  // here we are going to use comma separated variables, so end the filename with .csv
  // If I am on a normal windows desktop the open command will be something like:
  output.open("C:/Documents and Settings/Paul Johnson/My Documents/Data/test.csv");
  // If I am on a university cluster windows machine the open command will be something like:
// output.open("P:/Data/test.csv");
  // If I am on a unix machine the open command will be something like:
// output.open("/home/pjohnson/Data/test.csv");
  if(!output.is_open())
  {
    // NOTE!!!! The file will not open unless the directory exists!!!
    std::cout << " File not opened \n";
    // stop the program here
    throw;
  }
  // write x vs x^2 to a file
  for(int i=0;i<11;i++)
  {
    double x=i*0.1;
    output << x << " , " << x*x << std::endl; 
  }
  // file write successful then close file
  std::cout << " File write successful \n";
  output.close();
  // on visual studio you need to pause terminal
  system("pause");
  return 0;
}