Sum multiples of 3 and 5: Difference between revisions

=={{header|8th}}==

Implements both the naive method and inclusion/exclusion.

<lang 8th>

needs combinators/bi

: mul3or5? ( 3 mod 0 = ) ( 5 mod 0 = ) bi or ;

"The sum of the multiples of 3 or 5 below 1000 is " .

0 ( mul3or5? if I n:+ then ) 1 999 loop . cr

with: n

: >triangular SED: n -- n

dup 1+ * 2 / ;

: sumdiv SED: n n -- n

dup >r /mod nip >triangular r> * ;

: sumdiv_3,5 SED: n -- n

( swap sumdiv ) curry [3, 5, 15] swap a:map a:open neg + + ;

;with

"For 10^20 - 1, the sum is " . 10 20 ^ 1- sumdiv_3,5 . cr

bye

</lang>

{{Out}}

<pre>

The sum of the multiples of 3 or 5 below 1000 is 233168

For 10^20 - 1, the sum is 2333333333333333333316666666666666666668

</pre>