recursive method problem

[melody]

a) What is the output of the following recursive code?

public static void main(String[] args){
System.out.println(foo(4));
}

public static int foo(int n){
System.out.println(n);
if (n == 0)
return n;
else
return n + foo(n - 1);
}

b) Write a recursive method that accepts a single String as a parameter and returns ther reverse of that String. For example, calling the method reverse("Test")would return the String "tseT."



My answer is these? are those right? thank you
(a)
4
3
2
1
0
10

(b)
public static String reverse(String str) {
if (str == null || str.length() == 0)
return null;
else if (str.length() == 1) {
return str;
} else
return str.charAt(str.length() - 1)+reverse(str.substring(0, str.length() - 1));
}

[r035198x]

Again you can run those snippets and see the results for yourself.