Möbius function: Difference between revisions

</pre>

=={{header|RPL}}==

{{trans|FreeBASIC}}

RPL does not allow that a function returns something whilst in the middle of a branch, so we have to play here with index saturation and flag use to mimic the short returns that many other languages accept.

{{works with|Halcyon Calc|4.2.7}}

{| class="wikitable"

! RPL code

! Comment

|-

|

≪

'''IF''' DUP 1 ≠ '''THEN''' → n

≪ -1

2 n √ '''FOR''' d

'''IF''' n d MOD NOT '''THEN'''

1 CF '''IF''' n d SQ MOD NOT '''THEN'''

n 'd' STO DROP 0 1 SF '''END'''

'''IF''' 1 FC? '''THEN'''

DROP n d / n 'd' STO '''MU''' NEG '''END'''

'''END'''

'''NEXT'''

≫ '''END'''

≫ ''''MU'''' STO

|

'''MU''' ''( n -- µ(n) )''

if n = 1 then return 1

// default return value put in stack

for d as uinteger = 2 to int(sqr(n))

if n mod d = 0 then

if n mod (d*d) = 0 then

return 0 // and set flag

// if flag not set,

return -mobius(n/d)

end if

next d

|}

{{in}}

<pre>

≪ 1 100 FOR li "" li DUP 19 + FOR j "-0+" j MU 2 + DUP SUB + NEXT 20 STEP ≫ EVAL

</pre>

{{out}}

<pre>

5: "+--0-+-00+-0-++0-0-0"

4: "++-00+00---0+++0-++0"

3: "---00+-000+0-0+0++-0"

2: "-+00+--0+--0-+00+--0"

1: "0+-0+++0-0+0+++0-000"