Middle three digits: Difference between revisions

{{incorrect|REXX|--(version 1)-- the subroutine/function doesn't return the middle three digits as per the task's description. <br>}}

===version 1===

</pre>

===version 2===

A premise: &nbsp; '''12.3e2''' &nbsp; is an integer &nbsp; (regardless of how it's displayed).

<br>So is a &nbsp; '''googol''' &nbsp; and a &nbsp;'''googleplex'''.

<br><br>This REXX version is limited to numbers whose absolute value ≤ 100,000 digits.

<lang rexx>/*REXX program returns the 3 middle digits of a number (or an error). */

n ='123 12345 1234567 987654321 10001 -10001 -123 -100 100 -12345',

'2 -1 -10 2002 -2002 0 abc 1e3 -17e-3 1234567. 1237654.00',

'1234567890123456789012345678901234567890123456789012345678901234567'

do j=1 for words(n); z=word(n,j) /* [↓] format the output nicely.*/

say 'middle 3 digits of' right(z,max(15,length(z))) '──►' middle3(z)

end /*j*/

exit /*stick a fork in it, we're done.*/

/*──────────────────────────────────MIDDLE3 subroutine──────────────────*/

middle3: procedure; arg x; numeric digits 1e5; er=' ***error!*** '

if datatype(x,'N') then x=abs(x)/1; L=length(x)

if \datatype(x,'W') then return er "arg isn't an integer"

if L<3 then return er "arg is less then three digits"

if L//2==0 then return er "arg isn't an odd number of digits"

return substr(x, (L-3)%2+1, 3)</lang>

'''output'''

<pre style="overflow:scroll">

middle 3 digits of 123 ──► 123

middle 3 digits of 12345 ──► 234

middle 3 digits of 1234567 ──► 345

middle 3 digits of 987654321 ──► 654

middle 3 digits of 10001 ──► 000

middle 3 digits of -10001 ──► 000

middle 3 digits of -123 ──► 123

middle 3 digits of -100 ──► 100

middle 3 digits of 100 ──► 100

middle 3 digits of -12345 ──► 234

middle 3 digits of 2 ──► ***error!*** arg is less then three digits

middle 3 digits of -1 ──► ***error!*** arg is less then three digits

middle 3 digits of -10 ──► ***error!*** arg is less then three digits

middle 3 digits of 2002 ──► ***error!*** arg isn't an odd number of digits

middle 3 digits of -2002 ──► ***error!*** arg isn't an odd number of digits

middle 3 digits of 0 ──► ***error!*** arg is less then three digits

middle 3 digits of abc ──► ***error!*** arg isn't an integer

middle 3 digits of 1e3 ──► ***error!*** arg isn't an odd number of digits

middle 3 digits of -17e-3 ──► ***error!*** arg isn't an integer

middle 3 digits of 1234567. ──► 345

middle 3 digits of 1237654.00 ──► 376

middle 3 digits of 1234567890123456789012345678901234567890123456789012345678901234567 ──► 345