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 int sum(){
	int sum = 0;
	for (int i = 0; i<a.length; i++){
	    sum = sum + a[i];
	}
	return sum;
    }
    public double mean(){
	int sum = sum();
	return sum/(double)a.length;
    }
    public double stddev(){
	double mean = mean();
	double[] temp = new double[a.length];
	for (int i = 0; i <a.length; i++){
	    temp[i] = Math.pow(a[i]-mean,2);
	}
	double sum1 = 0;
	for (int i =0; i<temp.length; i++){
	    sum1 = sum1 + temp[i];
	}
	double mean2 = sum1/(double)temp.length;
	
	return Math.sqrt(mean2);
    }
	

}