public void stringReverse(char[] characters){
   for (int i = 0; i < characters.length; i++){
	   System.out.print(characters[characters.length - i -1]);
   }
}

public class Test{
	
	public static void main(String[] args){
		Test test = new Test();
		String testString = "Click the Post Message button to submit your message immediately.";
		test.stringReverse(testString.toCharArray());
		System.exit(0);
	}
	
	 public void stringReverse(char[] characters){
		for (int i = 0; i < characters.length; i++){
		   System.out.print(characters[characters.length - i -1]);
	    }
	}
	
}

	public void stringReverse(char[] characters){ 
		if (characters.length > 0){
			System.out.print(characters[characters.length -1]);
			char[] temp = new char[characters.length -1];
			for (int i = 0; i < temp.length; i++){	   
				temp[i] = characters[i];   
			}
			stringReverse(temp);
		}		
	}

	public void stringReverse(char[] characters){ 
		if (characters.length > 0){
			System.out.print(characters[characters.length -1]);
			stringReverse(String.copyValueOf(characters, 0, characters.length -1).toCharArray());
		}		
	}

/*	IntegerTest.java
*	@author: Charles Bell
*	@version: Nov 9, 2002
*/

import javax.swing.*;

/**	Problem:
*	Use a single-subscripted array to solve the following problem. 
*	Read in 20 numbers, each of which is between 10 and 100, inclusive.
*	As each number is read, print it only if it is not a duplicate of a 
*	number already read. Provide for the "worst case" in which all 
*	20 numbers are different. Use the smallest possible array 
*	to solve this problem 
*/
public class IntegerTest{

	/* a single-subscripted array */
	private int[] numbers;
		
	/*  between 10 and 100, inclusive. */
	private int min = 10;
	private int max = 100;
		
	/* 20 numbers */
	private int problemSize = 20;
	private boolean debug = true;


	public static void main(String[] args){
		IntegerTest test = new IntegerTest();
		test.runProblem();
		System.exit(0);
	}
	
	/*	Does all the work to complete the problem. 
	*/
	public void runProblem(){
		String message = "Enter a number between " 
			+ String.valueOf(min) + " and " 
			+ String.valueOf(max) + " inclusive.";
		/* Read in 20 numbers */
		for (int i = 0; i < problemSize; i++){
			int nextNumber = getNumberInRange(message);
			if (!testNumber(nextNumber, numbers)){
				if (numbers == null) {
					numbers = new int[1];
					numbers[0] = nextNumber;
				}else{
					/*	The array size will only increase if a new number is input. */ 
					numbers = addArrayElement(nextNumber, numbers);
				}		
				/*	As each number is read, print it only if it is not 
				*	a duplicate of a number already read
				*/
				if (debug) System.out.println(nextNumber);
				JOptionPane.showMessageDialog(null, String.valueOf(nextNumber));
			}			
		}
		if (debug) System.out.println("numbers input: " + problemSize);
		/*	The array size will be equal to the problemSize if all different numbers are entered. */ 
		/*	The array size will be less than the problemSize if duplicate numbers were entered. */ 
		if (debug) System.out.println("array size: " + numbers.length);
		if (debug) {
			for (int i = 0; i < numbers.length; i++){
				System.out.println("numbers[" + i + "] = " + numbers[i]);
			}
		}
	}
	
	/**	Uses a JOptionPane input dialog to request a number string from the 
	*	the user, providing the user an input message. Checks to ensure the 
	*	number input is in the range required by the problem. Loops until 
	*	range requirement is met.
	*/
	private int getNumberInRange(String inputMessage){
		int n = -1;
		while ((n < min) || (n > max)){
			String input = JOptionPane.showInputDialog(null, inputMessage);
			try{
				n = Integer.parseInt(input);	
				if ((n < min) || (n > max)) JOptionPane.showMessageDialog(null, 
					"That was an invalid integer. Try again.",
					"Error", JOptionPane.ERROR_MESSAGE);
			}catch(NumberFormatException nfe){
				n = -1;
				System.err.println("NumberFormatException: " + nfe.getMessage());
				JOptionPane.showMessageDialog(null, "That was invalid. Try again.",
					"Error", JOptionPane.ERROR_MESSAGE);
			}			
		}
		return n;		
	}

	/*	Test a number to see if in input array.
	*/
	private boolean testNumber(int n, int[] array){
		boolean testStatus = false;
		if (array != null){
			for (int i = 0; i < array.length; i++){
				if (n == array[i]) testStatus = true;
			}
		}
		return testStatus;		
	}
	
	/**	Creates a new array from intarray adding an element with value n.
	*/
	public int[] addArrayElement(int n, int[] intarray){
		int[] newarray = new int[intarray.length + 1];
		for (int i = 0;i < intarray.length;i++){
			newarray[i] = intarray[i];
		}
		newarray[intarray.length] = n;
		return newarray;
	}

}