package com.company;
import java.util.Scanner;
import java.io.FileWriter;

public class Main {
    public static float Epsilon(double LimitEps) {
        boolean isInCorrect = true;
        float Eps;
        do {
            try {
                Scanner num = new Scanner(System.in);
                Eps = num.nextInt();
                if ((Eps > 1) || (Eps < LimitEps)) {
                    System.out.format("Your number must belong to the range of [%d..%d]!\n",
                            0, LimitEps);
                } else
                    isInCorrect = false;
            } catch (Exception e) {
                System.out.println("Enter a correct value!");
            }
        }
        while (isInCorrect);
        return Eps;
    }

    public static float FunctionArgument(double limitX) {
        boolean isInCorrect = true;
        float x;
        do {
            try {
                Scanner num = new Scanner(System.in);
                x = num.nextInt();
                if ((x < 0) || (x > limitX)) {
                    System.out.format("Your number must belong to the range of [%d..%d]!\n",
                            0, limitX);
                } else
                    isInCorrect = false;
            } catch (Exception e) {
                System.out.println("Enter a correct value!");
            }
        }
        while (isInCorrect);
        return x;
    }


    public static double MaclaurinSeries(float Eps, float x) {
        double y = 0.0, value = 0.0;
        double factorial = 1.0, power = x, sign = 1.0;
        int n = 1;
        do {
            value = power / factorial;
            y += sign * value;
            n++;
            sign *= -1.0;
            power *= x * x;
            factorial *= (float) (2 * n - 1) * (2 * n - 2);
        } while (value > Eps);
        return y;
    }

    public static void Input(float Eps, float x, double result) {
        System.out.printf("%.4f ", Eps, x, result);
    }


    public static void WriteToFile(double y, String FName) throws Exception {
        int n;
        FileWriter FileOut = new FileWriter(FName);
        for (int i = 0; i < n; i++) {
            FileOut.write(y);
        }
        FileOut.write("\n");
        FileOut.close();
        System.out.println("Saved to file: " + FName);
    }


    public static void main(String[] args) {
        int[] Reduct;
        final double LimitEps = 0.000001;
        final double LimitX = 124;
        String FileNameOut;
        double y;
        float Eps, x;
        System.out.println("This program calculates the value of a function y = sin(x) with precision e by expanding the function in a Maclaurin series");
        Eps = Epsilon(LimitEps);
        x = FunctionArgument(LimitX);
        y = MaclaurinSeries(Eps, x);
        Input(Eps, x, y);
        FileNameOut = in.readLine();
        WriteToFile(y, FileNameOut);
    }
}