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@NikoZBK NikoZBK/ComputeDeviation.java Secret
Last active Nov 17, 2019

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ComputeDeviation
/*
* Name: Nikolay Ostroukhov
* Date: 11/9/19
* Course Number: 111
* Course Name: CSC
* Problem Number: Homework 8 -- Compute Standard Deviation
* Email: noostroukhov@student.stcc.edu
* Computes standard deviation of a file
*/
package hw8;
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] ";
// **********************************************
private static double power(double x, int exp) {
double result = 1.0;
for (int i = 1; i <= exp; i++)
result *= x;
return result;
}
private static double deviation(double[] x) {
double result = 0.0;
for (int i = 0; i < x.length; i++)
result += power(x[i] - mean(x), 2);
result /= x.length - 1;
return result = Math.sqrt(result);
}
private static double mean(double[] x) {
double result = 0.0;
for (int i = 0; i < x.length; i++)
result += x[i];
return result /= 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 process(Scanner sc, String args[]) throws IOException {
System.out.print("Enter filename: ");
URL url = new URL("https://cs.stcc.edu/~silvestri/csc111/" + sc.nextLine());
Scanner scanURL = new Scanner(url.openStream());
double[] arr = populateArray(scanURL);
double mean = mean(arr);
double deviation = deviation(arr);
System.out.printf("Mean: \t\t%.3f\nDeviation: \t%.3f", mean, deviation);
scanURL.close();
}
// **********************************************
private static boolean doThisAgain(Scanner sc, String prompt) {
System.out.print(prompt);
String doOver = sc.nextLine();
return doOver.trim().equalsIgnoreCase("Y");
}
// **********************************************
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);
}
}
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