Mean.java

import java.util.Scanner;

/*
 *   G = e ** {1/n * sum i=1^n (log(x[i])) }
 *   H = n / sum_i=1^n (1/x[i])
 */

public class Mean {

   static final String FORMAT = "n=%d, geometric mean=%.2f, harmonic mean=%.2f%n";

   public static void main (final String[] args) {
      final Scanner stdin = new Scanner (System.in, "US-ASCII");
      double product = 0.0;
      double sum = 0.0;
      int count = 0;
      while (stdin.hasNextDouble()) {
         final double d = stdin.nextDouble();
         product += Math.log(d);
         sum += (1.0/d);
         count++;
      }
      if (count == 0) {
         System.out.printf ("n=0%n");
      } else {
         System.out.printf (FORMAT, count, Math.exp(product/count), count/sum);
      }
   }
}