ArrayStuff.java

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

    public double stddev(){
	double mean = this.mean();
	double sum = 0;
	double sq = 0;

	for (int i = 0; i< a.length; i++){
	   sq =  Math.pow(a[i]-mean,2);
	}
	double mean2 =  sq/a.length;
	double stddev = Math.sqrt(mean2);
	return stddev;
    }
	
	   
}