/*
  ReverseText
  written by Keith Fenske
  Sunday, 12 May 2002
  Copyright (c) 2002 by Keith Fenske.  All rights reserved.

  This Java program reverses a string using only the String.charAt(),
  String.equals(), and String.length() methods.  Input is read from the
  user in a loop until the input is the string "*" (only an asterisk
  character).
*/

import cs1.Keyboard;              // import Lewis/Loftus keyboard class
//                           http://duke.csc.villanova.edu/jss/keyboard.html

public class ReverseText
{
  public static void main(String[] args)
  {
    String user;                  // user's input string

    do
    {
      System.out.println("\nPlease type a string (or * to quit):");
      user = Keyboard.readString();
      System.out.println("\noriginal string: \"" + user + "\"");
      System.out.println("reversed string: \"" + reverse(user) + "\"");
      System.out.println("original string: \"" + user + "\"");
    } while (! user.equals("*"));

  } // end of main()


/*
  reverse() method

  This method takes one string parameter and returns a string result.  The
  characters in the result string are in reverse (opposite) order compared
  to the characters in the parameter string.

  Note that the parameter string can have zero or more characters.  We start
  by setting the result string to an empty string.  Then we append one
  character at a time from the parameter string.
*/
  static String reverse(String input)
  {
    int i;                        // index variable in "for" loop
    int length;                   // length of parameter string
    String result;                // our result string

    result = "";                  // start with empty result string
    length = input.length();      // get number of characters
    for (i = (length-1); i >= 0; i --) // backwards order
      result = result + input.charAt(i); // append one character to result

    return result;                // finished

  } // end of reverse()

} // end of class