CSC-111 HW8 Calculates the Standard Deviation of Numbers in a File

StdDevApp.java

/*
 * Name: Antonio C. Silvestri
 * Date: 11/28/2018
 * Course Number: CSC-111
 * Course Name: Introduction to Java
 * Problem Number: HW8
 * Email: silvestri@stcc.edu
 * Description:  Calculates the Standard Deviation of Numbers in a File
 */

import java.io.File;
import java.io.FileNotFoundException;
import java.util.Scanner;

public class StdDevApp {
	
	private static void report(double[] data, double mean, double dev) {
		// Print Data
		for (int i = 0; i < data.length; i++) {
			System.out.printf("%7.2f", data[i]);
			if ((i + 1) % 10 == 0)
				System.out.println();			
		}
		System.out.println();
		System.out.printf("The mean is %7.2f\n", mean);
		System.out.printf("The standard deviation is %7.5f\n", dev);
	}

	//**********************************************************
	
	private static double deviation(double[] data) {
		if (data.length < 2)
			return Double.NaN;
		double mean = mean(data);
		double sum = 0;
		for (int i = 0; i < data.length; i++)
			sum += Math.pow(data[i] - mean, 2);
		double dev = Math.sqrt(sum / (data.length - 1));
		return dev;		
	}

	//**********************************************************
	
	private static double mean(double[] data) {
		if (data.length < 1)
			return Double.NaN;
		double sum = 0;
		for (int i = 0; i < data.length; i++)
			sum += data[i];
		double ave = sum / data.length;
		return ave;
	}

	//**********************************************************
	
	private static double[] getData(Scanner sc) {
		int n = sc.nextInt();
		double data[] = new double[n];
		for (int i = 0; i < n; i++)
			data[i] = sc.nextDouble();
		return data;
	}
	
	//**********************************************
	
	private static void process(Scanner sc, String args[]) throws FileNotFoundException {
		System.out.print("Enter Datafile name: ");
		String filename = sc.nextLine();
		File file = new File(filename);
		Scanner scfile = new Scanner(file);
		double data[] = getData(scfile);
		scfile.close();
		double mean = mean(data);
		double dev = deviation(data);
		report(data, mean, dev);
	}
	
	//**********************************************
	
	private static boolean doThisAgain(Scanner sc, String prompt) {
		System.out.print(prompt);
		String doOver = sc.nextLine();
		return doOver.equalsIgnoreCase("Y");
	}
	
	//**********************************************
	
	public static void main(String args[]) throws FileNotFoundException {
		final String TITLE = "Standard Deviation Calculator App V1.0";
		final String CONTINUE_PROMPT = "Do this again? [y/N] ";
		
		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);
	}

}