//	File:  DataListTester.java   (requires Java 1.5 or newer)

//  Purpose: reads any number of integer test scores entered by the user,
//           and computes and prints the average, largest score, and deviation
//           of each score from the average.

//	The DataList class has an instance variable that is an ArrayList, and 
//  methods that add a value to the list, return the largest value, return
//  the average value, and print a table showing each value and its deviation
//  from the average.

//	Demonstrates
//	  0. a generic "ArrayList of Integer" 
//    1. traversing an ArrayList using a for statement
//    2. ArrayList methods size, add, and get 
//    3. Autoboxing and autounboxing

import java.util.* ;				// for ArrayList and Scanner

class DataList
{
	private ArrayList<Integer> list ;		// ArrayList instance var
	
	// constructor creates an empty list
	public DataList()
	{
		list = new ArrayList<Integer>() ;	
	}

	// add a score to the list
	public void add(int score)
	{
		list.add(score) ;		// autoboxing	
	}
	
	// is the list empty?
	public boolean isEmpty()
	{
		return list.size() == 0 ;		
	}
	
	// compute and return the average of the scores
	public double getAverage()
	{
		int sum = 0 ; 			// initialize accumulator
		
		// for each item on the list
		for (int index = 0 ; index < list.size() ; index++)
		{
			sum = sum + list.get(index) ;	// autounboxing
		}
		
		// compute the floating point average
		double average = (double)sum / list.size() ;
		
		return average ;
	}

	// return the largest score
	public int getMaximum()
	{
		if ( isEmpty() )			// if empty list, return 0 
		  return 0 ;
		
		int maxPos = 0 ; 			// assume largest is in position 0
		
		// for all other items on the list
		for (int index = 1 ; index < list.size() ; index++)
		{
			// if current int > largest so far...
			if ( list.get(index) > list.get(maxPos) )
			   maxPos = index ;		// update position of largest
		}
		
		// return the int at position "maxPos" of list
		return list.get(maxPos) ;
	}

	// print table showing all values and their deviations from the average
	public void printTable()
	{
		if ( this.isEmpty() )		// if no data entered...
		{
			System.out.println("Sorry, there was no data entered!") ;
			return ;				// ...we're outa here!
		}
		
		// print headings
		System.out.println
		       ("\n" + Align.right("Score",10) +  Align.right("Deviation",14)) ;
		System.out.println
		              (Align.right("=====",10) +  Align.right("=========",14)) ;
	
		double average = getAverage() ;		// compute average

		// for each item on the list...
		for (int index = 0 ; index < list.size() ; index++)
		{
			// get next item
			int score = list.get(index) ;
			
			// compute deviation of current score from average
			double difference = score - average ;

			System.out.println( Align.right(score, 10) + 
			                    Align.right(difference,14,2) ) ;
		}
		System.out.println() ;
	}
}

public class DataListTester
{
	public static void main (String[] args)
	{
		DataList data = new DataList() ;
		
		Scanner scan = new Scanner(System.in) ;
		
		// "priming" read
		System.out.println("Enter any number of scores separated by spaces " +
		                   "on any number of lines.\n(When done, enter " +
		                   "^Z on a line by itself)\n") ;
		               
		while ( scan.hasNext() )
		{
			int score = scan.nextInt() ;
			data.add(score) ;
		}

		if ( ! data.isEmpty() )		// if there was data, get statistics
		{
			data.printTable() ;
			double average = data.getAverage() ;
			System.out.println("Average score = " + Align.left(average,0,2) ) ;
			System.out.println("Largest score = " + data.getMaximum() ) ;
		}
		else
		{
			System.out.println( "ERROR - No data!" ) ;
		}		
	}
}

/* sample output from 2 runs

Enter any number of scores separated by spaces on any number of lines.
(When done, enter ^Z on a line by itself)

81 93
87 94 92
^Z

     Score     Deviation
     =====     =========
        81         -8.40
        93          3.60
        87         -2.40
        94          4.60
        92          2.60

Average score = 89.40
Largest score = 94


Enter any number of scores separated by spaces on any number of lines.
(When done, enter ^Z on a line by itself)

^Z

ERROR - No data!

*/