/**
 * Recursion exercise.
 */
public class Recurse {

    /**
     * Returns the first character of the given String.
     */
    public static char first(String s) {
        return s.charAt(0);
    }

    /**
     * Returns all but the first letter of the given String.
     */
    public static String rest(String s) {
        return s.substring(1);
    }

    /**
     * Returns all but the first and last letter of the String.
     */
    public static String middle(String s) {
        return s.substring(1, s.length() - 1);
    }

    /**
     * Returns the length of the given String.
     */
    public static int length(String s) {
        return s.length();
    }

}