import java.io.*;
    
/**
 *  Summer adds the values in a after application of the function func
 * 
 * @author CS1711 Instructors
 * @version 2003-10-15
 */
public class Summer
{
    // instance variables 
    private int[] a;
    private int sum;

    /**
     * Constructor for objects of class Summer
     */
    public Summer(int aSize)
    {
        // initialise instance variables
        a = new int[aSize];
    }
    
    /**
     * this gets terminal input for new values in a
     * 
     */
    public void readInput()
    { try{
      InputStreamReader reader = new InputStreamReader(System.in);
      BufferedReader console = new BufferedReader(reader); 
      System.out.println("Enter " + a.length + " numbers, one per line:");
      for (int i = 0; i < a.length; i++){
          System.out.print(">");
          String input = console.readLine();
          a[i] = Integer.parseInt(input);
      } 
      }
      catch(IOException exception) {
        System.out.println("Enter a number:");
      }      
    }
    

    /**
     * does the summing
     * 
     * @return     the sum of a[i]
     */
    public int sumup()
    {
        // init sum to 0, then add up
        sum = 0;
        for (int i =0; i < a.length; i++){
          sum += func(i);
        }
        return sum;
    }
     /**
     * applies a function to a[i]
     * 
     * @return     the function applied to a[i]
     */
    public int func(int i)
    {
        return a[i]*a[i];
    }
    
    /**
     * tests the sumup and readInput methods
     * 
     */
    public void sumTester()
    {
        // init set a[i] = i
        for (int i =0; i < a.length; i++){
          a[i] = i+1;
        }
        int theSum = sumup();
        System.out.println("The sum is " + theSum);
        readInput();
        theSum = sumup();
        System.out.println("The sum of entries is " + theSum);
        
    }
    
}