## December 21, 2008

at
Sunday, December 21, 2008
Labels:
Computer Science,
Lisp,
Project Euler
Posted by
Billy

2^(15) = 32768 and the sum of its digits is

3 + 2 + 7 + 6 + 8 = 26.

What is the sum of the digits of the number 2^(1000)?

(defun add-digits (num)

"Returns the sum of the number's digits"

(let ((sum 0)

(num-string (write-to-string num)))

(dotimes (i (length num-string))

(setf sum (+ sum (digit-char-p (schar num-string i)))))

sum))

(defun euler-16 ()

(add-digits (expt 2 1000)))

Subscribe to:
Post Comments (Atom)

## 0 comments:

Post a Comment