Midterm Project - Christopher Turner - Flintridge Preparatory School

NthRoot.java

import java.util.*; //Imports
public class NthRoot {
    public static void main(String[] args) {
        Calculator rootFinder = new Calculator(); //Creates a new calculator object from the class (simply for modularizing my code)
        double radical = (double) rootFinder.getRadical(); //Gets the number x that you want to find the nth root of
        int n = rootFinder.getN(); //Gets the number n to find the nth root of "radical"
        int requestedError = rootFinder.getRequestedError(); //Gets the integer P to find the error tolerated in the form 10E-P
        double xtoN = radical; //Creates a variable for the final result, initially setting it equal to the input
        double calculatedError = Math.pow(10, -(requestedError)); //Inserts the requestedError as the exponent P in 10E-P, to calculate the threshold where an answer over is wrong but an answer under is correct
        while (Math.abs(radical - Math.pow(xtoN,n)) > calculatedError) { //Runs while the difference between the inital input and the result to the nth power are greater than the error threshold
            xtoN = xtoN - ((Math.pow(xtoN,n) - radical) / (n * Math.pow(xtoN,n-1))); //Calculates the iterative result based on Newton's method
        }
        System.out.print("Your result is: "); //Output
        System.out.printf("%." + requestedError + "f", xtoN); //Output, formatted to the proper number of decimal places
    }
}
public class Calculator {
    Scanner input = new Scanner(System.in);
    int radical = -1; //Initializes a variable for the number a user would like to find the root of
    int n = -1; //Initializes a variable for the number a user would like to find the root of
    int requestedError = -1; //Initiatizes a variable for the number of decimal places a result will be accurate to
    public int getRadical() {
        System.out.println("Please enter a number to find the root of (for example, '500'):"); //Output
        while (radical < 1 || radical > 1000) { //Restricts calculuations to between 1 and 1000.
            while (input.hasNextInt() == false) { //Runs while the input doesn't include an integer
                input.nextLine(); //Advances to next line
            }
            radical = input.nextInt(); //Assigns the radical variable to user input
            if (radical > 0 && radical < 1001) { //Asks for new input if not within specified range
                System.out.println("You've chosen to find the nth root of " + radical + "."); //Output
            }
            else {
             System.out.println("A default value of 500 has been chosen for you."); //Output
             radical = 500;
            }
        }
        return radical;
    }
    public int getN() {
        System.out.println("Please enter n for the nth root (for example, '2'):"); //Output
        while (n < 1 || n > 100) { //Restricts calculuations to between 1 and 100.
            while (input.hasNextInt() == false) { //Runs while the input doesn't include an integer
                input.nextLine(); //Advances to next line
            }
            n = input.nextInt(); //Assigns the radical variable to user input
            if (n > 0 && n < 101) { //Asks for new input if not within specified range
                System.out.println("You've chosen the " + n + " root."); //Output
            }
            else {
             System.out.println("A default n of 2 has been chosen for you."); //Output
             n = 2; //Sets to a default
            }
        }
        return n;
    }
    public int getRequestedError() {
        System.out.println("Please enter P, your error tolerance in the form '10E-P, between 1 and 15:'"); //Ouput
        while (requestedError < 1 || requestedError > 15) { //Restricts range of calculations
            while (input.hasNextInt() == false) { //Runs while the input doesn't include an integer
                input.nextLine(); //Advances to next line
            }
            requestedError = input.nextInt(); //Assigns the radical variable to user input
            if (requestedError > 0 && requestedError < 16) { //Asks for new input if not within specified range
                System.out.println("You've chosen an error tolerance of 10E-" + requestedError + "."); //Output
            }
            else {
             System.out.println("A default error tolerance of 10E-5 has been chosen for you."); //Output
             requestedError = 5; //Sets to a default
            }
        }
        return requestedError;
    }
}