/***********************************************
The school cafeteria sells food to about 1000 students
each day. They have a program to record the amount paid
for each transaction.  The result is a text file on 
the disk containing all the numbers paid each day.
************************************************/

import java.io.*;

public class PricesSaver
{
  double[] nums = new double[10000];
  int count = 0;                  // number of items in NUMS
  
  public PricesSaver()
  {
    double price = 0;
    while(price >= 0)         // type -1 at the end of the day
    { 
      price = Double.parseDouble( input("Price") );
      if(price >= 0)
      {
        nums[count] = price;
        count = count+1;
      } 
    }
    saveNumbers();
    stats();
  }
  
  void saveNumbers()
  {
    try
    {
      BufferedWriter file = new BufferedWriter(
                             new PrintWriter("prices.dat")
                            );
      for(int c=0; c < count; c = c+1)
      {
        file.write(nums[c]+"\n");
      }
      file.close();
    }
    catch(IOException ex)
    {  System.out.println(ex.toString()); }
  }
  
  void stats()
  {
    double sum = 0;
    for(int c=0; c < count; c = c+1)
    {  
      sum = sum + nums[c];
    } 
    System.out.println("Total = " + sum);
    System.out.println("Average = " + sum / count);
  }
  
  public static void main(String[] args)
  {  new PricesSaver(); }
  
  public String input(String prompt)
  { return javax.swing.JOptionPane.showInputDialog(null,prompt); }
  
  public void output(String message)
  {  javax.swing.JOptionPane.showMessageDialog(null,message);  }
}