Task

The objective is to write a function that finds the sum of all positive multiples of 3 or 5 below n.

Show output for n = 1000.

This is is the same as Project Euler problem 1.

Extra credit: do this efficiently for n = 1e20 or higher.




: main ( n -- )
  0 swap
  3 do
    i 3 mod 0= if
      i +
    else i 5 mod 0= if
      i +
    then then
  loop
  . ;
 
1000 main    \ 233168  ok