ArrayStuff.java

import java.io.*;
import java.util.*;

public class ArrayStuff {
    private int[] a;
    private Random r;

    public ArrayStuff() {
	r = new Random();
	a = new int[20];
	for (int i=0;i<a.length;i++) 
	    a[i]=r.nextInt(100);
    }

    public String toString() {
	return Arrays.toString(a);
    }

    public int get(int n) {
	return a[n];
    }

    public int findMaxIndex() {
	int maxi = 0;
	for (int i =0 ; i < a.length;i++) {
	    if (a[i]>a[maxi]) 
		maxi = i;
	}
	return maxi;
    }

    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 = sum + a[i];
	}
	return sum/a.length;
    }

    public double stddev() {
	double mean = mean();
	double x = 0;
	for (int i=0; i<a.length; i++) {
	    x = x + (mean - a[i]) * (mean - a[i]);
	}
	return Math.sqrt( x/a.length );
    }

}