/*
 * Kyle Pierce
 * CSE 143
 *
 * Some more recursive methods
 */
import java.util.*;

public class Recursion2 {
   public static void main(String[] args) {
      System.out.println("The stutter of 348 is " + stutter(348));

      int[] arr = {3, 1, -4, 7, 2};
      System.out.println("The sum of " + Arrays.toString(arr) + " is " + sum(arr));
   }

   // post: returns the integer obtained by replacing every digit in n with
   //       two of that digit.  For example, stutter(348) returns 334488.
   public static int stutter(int n) {
      if (n < 0) {
         return -stutter(-n);
      } else if (n < 10) {
         return n * 11;
      } else {
         return stutter(n / 10) * 100 + stutter(n % 10);
      }
   }

   // post: returns the sum of the numbers in list
   public static int sum(int[] list) {
      return sum(list, 0);
   }

   // pre:  0 <= index <= list.length 
   // post: returns the sum of list starting at the given index 
   private static int sum(int[] list, int index) {
      if (index == list.length) {   
         return 0;
      } else {
         return list[index] + sum(list, index + 1);
      }
   }
}