// Lab 3 Lecture 1


// -------------------------- File Input --------------------------------------

// We will need a new library that will allow us to import and 
// export data from a file. For this we can use the "fstream"
// library. Notice that we have included it in the program below. 
//
// File manipulation can be tricky when you are first learning it.
// It contains concepts that we have not yet learned, and for that 
// reason you may have better luck just memorizing the steps.
//
// 1.	Create an input file stream object. We will use this 
//	object to bridge the gap between our program and the 
//	input file (ifstream = input file stream).
//
// 	ifstream name;
//
// 2.	Open the file so that you can begin to read from it.
//
// 	name.open("file_name.txt");
//
// 3.	Import the data. Importing from a file is almost exactly like
//	importing from the console. Where we use "cin" to get data
//	from the console, we will use our ifstream object "name" to
//	import data from a file.
//
//	name >> x;
//
// 4.	You must close your file at the end.
// 	
//	name.close();

// -------------------------- File Input Example ------------------------------

// Lets look at a simple example to help clarify what we just went over.

// We need to first make a text file named "input_file_name.txt" and write
// our first and last name in it. Example : Jason Constanzo

// file stream library
#include <fstream>

#include <iostream>
using namespace std;

int main()
{
	// variables to hold what we bring in from the file
	string first;
	string second;

	// declare an input file stream object named fin (file in). 
	ifstream fin;

	// open the file with our newly created input file stream 
	// object. Note the file name is a string literal so 
	// it has double quotes around it.
	fin.open("input_file_name.txt");

	// Read in two entries from the file. Note that we use our 
	// input file stream object 'fin' exactly like we would
	// use 'cin' except instead of getting data from the user
	// we are retrieving it from a file. 
	fin >> first;
	fin >> second;
	
	// fin >> first >> second;  // We could also use this syntax
	
	// close the file
	fin.close();

	// print what we read in from file
	cout << "first : " << first << endl;
	cout << "second : " << second << endl;
	
	
	/*  **BEWARE**
	 * It is important to note ifstream will import items from
	 * the file in order, and it will keep track of where it 
	 * left off so that the next data you import will be 
	 * sequentially next to the previous piece of data imported.
	 * Space and newline characters indicate where one piece
	 * of data begins and ends when importing strings and numbers.
	 * That was a mouth full so lets look at an example.
	 * 
	 * E.g. if our input file is as follows:
	 *
	 * 1205 Dr Who
	 *
	 * The first time we import an item of data using "fin >> x;" it
	 * will pull in the number 1205 and put it into the variable 
	 * 'x'. The next time we import something using "fin >> y;"
	 * the string "Dr" will be put into the variable 'y'.
	 */
	 
// ----------------------------------------------------------------------------
	 
	return 0;
}