title: Recursively form an interger sum of all digit characters in a string?
body: <p>I need to recursively go through a string, and add up all the digits I come across and return the final answer. In my head, I feel that my return call should be the value of the integer I just came across + a recursive call to my function, only one place further in the string this time. Would anyone be willing to push me in the right direction here? Thanks!</p>