ComputeDeviation with Silvestri's modifications 11/9/2020

ComputeDeviation.java

/*
 * Name: Nikolay Ostroukhov (with Silvestri's Modifications)
 * Date: 11/9/20
 * Course Number: 111
 * Course Name: CSC
 * Problem Number: Homework 8 -- Compute Standard Deviation
 * Email: noostroukhov@student.stcc.edu
 * Computes standard deviation of a file
 */

import java.io.IOException;
import java.net.URL;
import java.util.Scanner;

public class ComputeDeviation {
	final static String TITLE = "Niko's Standard Deviation Calculator";
	final static String CONTINUE_PROMPT = "\nPerform another calculation? [y/N] ";

	//**********************************************
	// Put as many methods you need here

	private static double deviation(double[] x, double mean) {
		double result = 0.0;
		for (int i = 0; i < x.length; i++)
			result += Math.pow(x[i] - mean, 2);
		result /= x.length - 1;
		return Math.sqrt(result);
	}

	private static double mean(double[] x) {
		double sum = 0.0;
		for (int i = 0; i < x.length; i++)
			sum += x[i];
		return sum / x.length;
	}

	private static double[] populateArray(Scanner sc) {
		int count = sc.nextInt();
		double[] result = new double[count];
		for (int i = 0; i < count; i++)
			result[i] = sc.nextDouble();
		return result;
	}

	private static void printArray(double[] arr, int columns) {
		for (int i = 0; i < arr.length; i++) {
			System.out.printf("%10.5f", arr[i]);
			if ((i+1) % columns == 0)
				System.out.println();			
		}
		if (arr.length % columns != 0)
			System.out.println();
	}
	
	
	// **********************************************

	private static void process(Scanner sc, String args[]) throws IOException {
		// data-500-15-5.txt   data-750-10-6.txt     data-1000-20-10.txt
		System.out.print("Enter filename: ");
		String filename = sc.nextLine();
		URL url = new URL("https://cs.stcc.edu/~silvestri/csc111/" + filename);
		Scanner scanURL = new Scanner(url.openStream());

		double[] arr = populateArray(scanURL);
		double mean = mean(arr);
		double deviation = deviation(arr, mean);
		
		printArray(arr, 7);

		System.out.printf("Mean: %.3f\nDeviation: %.3f\n", mean, deviation);

		scanURL.close();
	}


	// **********************************************
	// Do not change the doThisAgain method
	private static boolean doThisAgain(Scanner sc, String prompt) {
		System.out.print(prompt);
		String doOver = sc.nextLine();
		return doOver.trim().equalsIgnoreCase("Y");
	}

	// **********************************************
	// Do not change the main method
	public static void main(String args[]) throws IOException {
		System.out.println("Welcome to " + TITLE);
		Scanner sc = new Scanner(System.in);
		do {
			process(sc, args);
		} while (doThisAgain(sc, CONTINUE_PROMPT));
		sc.close();
		System.out.println("Thank you for using " + TITLE);
	}

}