import java.util.Scanner;
import java.util.LinkedList;
import java.util.ListIterator;
import java.io.IOException;
import java.io.FileInputStream;

/** Program.java -- This file reads input for the cache simulation.
 *  Actually it's NOT a real program.  We just want a list of memory addresses
 *  that are referenced dynamically when a program executes.  I'm simply
 *  calling this the "program" class so that you see that the cache is
 *  running data from a program.
 *  Let's use a LinkedList of String (the lines of input containing addresses).
 */
public class Program
{
  private LinkedList<String> address;
  
  // Constructor for "program" class.
  // The purpose of the counter variable is to allow us to keep track
  // of which number to fetch while the simulation is running.
  public Program() throws IOException
  {
    address = new LinkedList<String>();
    
    Scanner kbd = new Scanner(System.in);
    System.out.printf("What is the name of the input file?  ");
    String fileName = kbd.nextLine().trim();
    Scanner in = new Scanner(new FileInputStream(fileName));
    
    while(in.hasNextLine())
    {
      String line = in.nextLine();
      address.add(line);
    }
  }
  
  // Give us a way to traverse the list of addresses from the beginning.
  public ListIterator listIterator()
  {
    return address.listIterator(0);
  }
}