; Written on Friday morning, January 23rd.
; Saved on Monday morning, January 26th (AFTER CLASS!)

(define sumOfDigits (lambda (number)
  (if (< number 10) number 
      (+ (modulo number 10) (sumOfDigits (quotient number 10))))))

                                               > (modulo 1234 10)
                                               4
                                               > (quotient 1234 10)
                                               123
Welcome to DrScheme, version 205.
Language: Intermediate Student with lambda.

> (sumOfDigits 12345678)
36
> (sumOfDigits 1234567)
28
> (sumOfDigits 807)
15
> (sumOfDigits 34)
7
> (sumOfDigits 1234)
10

(define sumOfDigits (lambda (number)
  (if (< number 10) number 
      (+ (modulo number 10) (sumOfDigits (quotient number 10))))))