public class StringRecursion
{
	public static void printLetters(String str)
	{
		if(str==null)
		{
			System.out.println(str);
		}
		else
		{
			System.out.print(str.charAt(0)+", ");
			str=str.substring(1, str.length());
			printLetters(str);
		}
	}

	public static void main(String[] args)
	{
		printLetters("Testing 123");
	}

}