import java.util.Scanner;
public class Rain 
{
    public static void main(String[] args)
    {
        // Declare and allocate an array of doubles of size 4
         double[] a;
         a = new double[4];

         // Explicitly initialize all 4 elements
         a[0] = 10.1;
         a[1] = 12.3;
         a[2] = 9.7;
         a[3] = 8.2;

         // Sum the elements
         double sum = 0;
         int i = 0;
         while (i < a.length){
            sum = sum + a[i];
            i = i + 1;
         }
         System.out.println(sum);

         // Reassign the elements by reading from the keyboard
         // The loop needs a prompt to tell the user to input a double
         Scanner s = new Scanner(System.in);
         i = 0;
         while (i < a.length){
            a[i] = s.nextInt();
            i = i + 1;
         }
        
         // Print all 4 elements, first to last
         i = 0;
         while (i < a.length){
         //while (i < 4){
            System.out.println("i is " + i + " a[i] is " +  a[i]);
            i = i + 1;
         }

         System.out.println( );

         // Print all 4 elements, last to first
         i = a.length - 1;
         while (i >= 0 ){
            System.out.println("i is " + i + " a[i] is " +  a[i]);
            i = i - 1;
         }
    }
}