EulersNumber.java

import java.util.Scanner;

public class EulersNumber {

    /**
    *   Program:    EulersNumber.java
    *   Purpose:    Calculate 1+x+x^2/2!+x^3/3!+...upto user input (Taylor Series) e^x (e=Euler's number)
    *   Creator:    Chris Clarke
    *   Created:    23.05.2015
    */

    public int factorial(int n) {
        return n == 1? 1 : n * factorial(n - 1);
    } // factorial()

    public void calcEuler(int x, int n) {
        double sum = 1.0;
        for (int t=1; t<=n; t++) {
            sum += Math.pow(x, t)/factorial(t);
        } // for
        System.out.printf("With x = %d and n = %d, result = %f%n", x, n, sum);
    } // calcEuler

    public static void main(String[] args) {
        EulersNumber e = new EulersNumber();
        Scanner in = new Scanner(System.in);
        int n, x;
        System.out.print("I will calculate Euler's number. Enter value for x: ");
        x=in.nextInt();
        System.out.print("Enter integer value for n: ");
        do {
            n = in.nextInt();
            if (n<1) System.out.print("Must be one or more: ");
        } while (n<1);
        e.calcEuler(x, n);
    } // main()

} // class EulersNumber