100 doors: Difference between revisions

=={{header|Dc}}==

'''Unoptimized''':

{{works with|dc|(GNU bc 1.06.95) 1.3.95}}

<lang Dc>

## NB: This code uses the dc command "r" via register "r".

## You may comment out the unwanted version.

[SxSyLxLy]sr # this should work with every "dc"

[r]sr # GNU dc can exchange top 2 stack values by "r"

## Now use "lrx" instead of "r" ...

0k # we work without decimal places

[q]sq # useful e.g. as loop termination

## (x)(y)>R == if (y)>(x) eval R

## isle x y --> (x <= y)

[

[1q]S. [ !<. 0 ]x s.L.

]sl

## l: isle

[

100 llx

]sL

## L: isle100

## for initcode condcode incrcode body

## [1] [2] [3] [4]

[

[q]S. 4:. 3:. 2:. 1:. 1;.x [2;.x 0=. 4;.x 3;.x 0;.x]d0:.x Os.L.o

]sf

## f: for

##----------------------------------------------------------------------------

## for( i=1 ; i<=100 ; ++i ) {

## door[i] = 0;

## }

#[init ...]P []ps-

[1si] [li lLx] [li1+si] [

li 0:d

]lfx

## for( s=1 ; s<=100 ; ++s ) {

## for( i=s ; i<=100 ; i+=s ) {

## door[i] = 1 - door[i]

## }

## }

[1ss] [ls lLx] [ls1+ss] [

#[step ]P lsn [ ...]ps-

[lssi] [li lLx] [lils+si] [

1 li;d - li:d

]lfx

]lfx

## long output:

## for( i=1 ; i<=100 ; ++i ) {

## print "door #", i, " is ", (door[i] ? "open" : "closed")), NL

## }

[

[1si] [li lLx] [li1+si] [

[door #]P

li n

[ is ]P

[closed]

[open]

li;d 0=r lrx s- n

[.]ps-

]lfx

]

## terse output:

## for( i=1 ; i<=100 ; ++i ) {

## if( door[i] ) {

## print i

## }

## print NL

## }

[

[1si] [li lLx] [li1+si] [

[] [ [ ]n lin ]

li;d 0=r lrx s- x

]lfx

[]ps-

]

lrx # comment out for the long output version

s- x

#[stack rest...]P []ps- f

</lang>

Output:

1 4 9 16 25 36 49 64 81 100