ArrayStuff.java

import java.io.*;
import java.util.Arrays;
import java.util.Random;

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]*1.0;
	}
	return sum/a.length;
    }
    public double mean(double[] nums) {
	double sum = 0.0;
	for (int i = 0; i < nums.length; i ++) {
	    sum = sum + nums[i];
	}
	return sum/nums.length;
    }

    public double stddev() {
	double mean = mean();
	double[] sqDiff = new double[a.length];
	for (int i = 0; i < a.length; i ++) {
	    double diff = (a[i]*1.0) - mean;
	    sqDiff[i] = diff * diff;
	}
	return Math.sqrt(mean(sqDiff));
    }
}