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CSC-111 HW8 Calculates the Standard Deviation of Numbers in a File
/*
* 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);
}
}
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