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[] nums){
		int sums = 0;
		for (int i = 0; i < nums.length; i++){
			sums += nums[i];
		}
		return (double)sums/nums.length;
	}

	public double sddev(int[] nums){
		int mean = mean(nums);
		int[] eachsq = new int[nums.length];
		for (int i=0; i<nums.length;i++){
			int r=nums[i]-mean;
			eachsq[i]=(r*r);
		}
		return Math.sqrt(mean(eachsq));
	}
}