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);
}
}