/*************************************************************************
 *  Compilation:  javac StdStats.java
 *  Execution:    java StdStats
 *
 *  Library of statistical functions.
 *
 *  The test client converts the command-line arguments to an array
 *  of doubles, and then calls min(), mean(), stddev(), and max(),
 *
 *  The functions all throw a NullPointerException if the array
 *  passed in is null.
 *
 *  %  java StdStats 3.0 1.0 2.0 5.0 4.0
 *  1.000000 3.000000 (1.414214) 5.000000
 *
 *  Remarks
 *  ------------
 *    - Should we compute sample variance and sample stddev (divide by N-1)
 *      instead of variance and stddev (divide by N) ?
 *  
 *************************************************************************/

public class StdStats {

   // return maximum value (-infinity if no such value)
   public static double max(double[] a) {
      double max = Double.NEGATIVE_INFINITY;
      for (int i = 0; i < a.length; i++)
         if (a[i] > max) max = a[i];
      return max;
   }

   // return minimum value (+infinity if no such value)
   public static double min(double[] a) {
      double min = Double.POSITIVE_INFINITY;
      for (int i = 0; i < a.length; i++)
         if (a[i] < min) min = a[i];
      return min;
   }

   // return average value (NaN if no such value)
   public static double mean(double[] a) {
      double sum = 0.0;
      for (int i = 0; i < a.length; i++)
         sum = sum + a[i];
      return sum / a.length;
   }

   // return variance (NaN if no such value)
   public static double var(double[] a) {
      double avg = mean(a);
      double sum = 0.0;
      for (int i = 0; i < a.length; i++)
         sum += (a[i] - avg) * (a[i] - avg);
      return sum / a.length;
   }

   // return standard deviation (NaN if no such value)
   public static double stddev(double[] a) {
      return Math.sqrt(var(a));
   }


   // return maximum value (overloaded for int values)
   public static int max(int[] a) {
      int max = Integer.MIN_VALUE;
      for (int i = 0; i < a.length; i++)
         if (a[i] > max) max = a[i];
      return max;
   }

   // return sum of all values (0 if no elements)
   public static int sum(int[] a) {
      int sum = 0;
      for (int i = 0; i < a.length; i++)
         sum += a[i];
      return sum;
   }




   // convert command-line arguments to array of doubles and call various methods
   public static void main(String[] args) { 

      // read in values from command line
      double[] a = new double[args.length];
      for (int i = 0; i < args.length; i++)
           a[i] = Double.parseDouble(args[i]);

      // print results
      StdOut.printf("%f %f (%f) %f\n", min(a), mean(a), stddev(a), max(a));
   }



}