우아하지는 않네요.ㅋㅋ
리팩토링 해봐야지.
문제
Each new term in the Fibonacci sequence is generated by adding the previous two terms. By starting with 1 and 2, the first 10 terms will be:
1, 2, 3, 5, 8, 13, 21, 34, 55, 89, ...
Find the sum of all the even-valued terms in the sequence which do not exceed four million.
Source
: sum-all-even-valued-of-fibonacci-until-4000000 ( x y z -- t ) [ dup swapd + dup 4000000 < [ dup even? [ dup roll + -rot t ] [ t ] if ] [ . . f ] if ] loop ;
: project-euler2 ( x y z -- ) 0 0 1 sum-all-even-valued-of-fibonacci-until-4000000 ;
