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 = 0.0;
	for(int i=0; i<a.length; i++){
	    sum = sum + a[i];
	}
	return (sum/a.length);
    }

    public double stddev(){
	double average = mean();
	double squaredsum = 0.0;
 
	for(int i=0; i<a.length; i++){
	    double difference = (a[i] - average);
	    squaredsum = squaredsum + difference*difference;
	}

	return (Math.sqrt(squaredsum/a.length));
    }
}