/* * Copyright (c) 2000 David Flanagan.  All rights reserved. * This code is from the book Java Examples in a Nutshell, 2nd Edition. * It is provided AS-IS, WITHOUT ANY WARRANTY either expressed or implied. * You may study, use, and modify it for any non-commercial purpose. * You may distribute it non-commercially as long as you retain this notice. * For a commercial use license, or to purchase the book (recommended), * visit http://www.davidflanagan.com/javaexamples2. */package com.davidflanagan.examples.basics;import java.io.*; // Import all classes in java.io package.  Saves typing./** * This program displays factorials as the user enters values interactively **/public class FactQuoter {    public static void main(String[] args) throws IOException {        // This is how we set things up to read lines of text from the user.        BufferedReader in=new BufferedReader(new InputStreamReader(System.in));        // Loop forever        for(;;) {            // Display a prompt to the user            System.out.print("FactQuoter> ");            // Read a line from the user            String line = in.readLine();            // If we reach the end-of-file, 	    // or if the user types "quit", then quit            if ((line == null) || line.equals("quit")) break;            // Try to parse the line, and compute and print the factorial            try {                 int x = Integer.parseInt(line);                System.out.println(x + "! = " + Factorial4.factorial(x));             }            // If anything goes wrong, display a generic error message            catch(Exception e) { System.out.println("Invalid Input"); }        }    }}