import javabook.*;

class Recursion
{
    public static void main(String[] args)
    {
		MainWindow mw = new MainWindow();
		mw.setVisible( true );
		InputBox in = new InputBox( mw );
		
		int number = in.getInteger( "Number, please:" );
		int fact = recursive_factorial( number );
		System.out.println( "-------------------" );
		System.out.println( number + "! = " + fact );

/*		int[] a = new int[10];
		for( int i=0; i < a.length; i++ )
			a[i] = (int)(Math.floor(Math.random() * 100) + 1);
		print( a, 0 );
		System.out.println("");
		number = sum( a, a.length );
		System.out.println( "Sum = " + number );
		
		String s = in.getString( "String, please:" );
		if( isPalindrome( s ) )
			System.out.println( s + " is a palindrome." );
		else
			System.out.println( s + " is not a palindrome." );*/
    }


    public static int recursive_factorial( int n )
    {
        if( n == 1 )
            return 1;

        int total = n * recursive_factorial( n - 1 );

        return total;
    }


    public static int factorial( int n )
    {
        int total = 1;
        for( int i = 2; i <= n; i++ )
        {
            total = total * i;
        }

        return total;
    }

	
	public static int sum( int[] a, int length )
	{
		if( length <= 0 )
			return 0;

		int partialSum = sum( a, length - 1 );
		return a[length-1] + partialSum;
	}

	
	public static void print( int[] a, int startingAt )
	{
		if( startingAt >= 0  &&  startingAt < a.length )
		{
			System.out.print( a[startingAt] + " " );
			print( a, startingAt + 1 );
		}
	}


	public static boolean isPalindrome( String s )
	{
		if( s.length() <= 1 )
			return true;

		if( s.charAt(0) != s.charAt(s.length()-1) )
			return false;

		return isPalindrome( s.substring( 1, s.length() - 1 ) );
	}
}