import java.util.*; import java.io.*; public class ArrayStuff{ private int[] a; private Random r = new Random(); public ArrayStuff() { a=new int[20]; for (int i=0;i<a.length;i++) { a[i]=r.nextInt(100); } } public String toString() { return Arrays.toString(a); } // return the index of the max element public int findMaxIndex() { if (a==null || a.length==0) return -1; int maxi = 0; for (int i=0;i<a.length;i++) { if (a[i] > a[maxi]) maxi = i; } return maxi; } public int get(int n) { if (n>=0 && n < a.length) return a[n]; else return -1; } public int find(int n) { for (int i=0;i<a.length;i++) { if (a[i]==n) return i; } return -1; } public double mean() { double sum = 0; for (int i = 0; i<a.length; i ++) { sum += a[i]; } return sum/(a.length + 0.0); } public double mean2 (double [] a) { double sum = 0; for (int i = 0; i<a.length; i ++) { sum += a[i]; } return sum/(a.length + 0.0); } public double stddev() { double b = mean(); double [] c = new double [a.length]; for (int x = 0; x<a.length;x ++) { c[x] = Math.pow(a[x] - b,2); } double d = mean2(c); return Math.pow(d, 0.5); } }