aparler/RosettaCodeData
1
0
Fork 0
Code Issues 12 Pull requests 3 Projects Releases Packages Wiki Activity Actions

Just another update

Browse source
This commit is contained in:
Ingy döt Net 2015-02-20 00:35:01 -05:00
parent a25938f123
commit 00a190b0a6
6591 changed files with 94363 additions and 23227 deletions
Download patch file Download diff file Expand all files Collapse all files

59
Task/Factorial/REXX/factorial-3.rexx
View file

@ -1,34 +1,27 @@
/*REXX program computes the factorial of a non-negative integer, and */
/* automatically adjusts the number of digits to accommodate the answer.*/
/*This version allows for faster multiplying of #s (no trailing zeros).*/
numeric digits 100 /*start with 100 digits. */
numeric form /*indicates we want scientric form*/
parse arg n .; if n=='' then n=0 /*get argument from command line. */
/*════════════════════════════════════where the rubber meets the road. */
!=1 /*define factorial product so far.*/
do j=2 to n /*compute factorial the hard way. */
o!=! /*save old ! in case of overflow. */
!=!*j /*multiple the factorial with J, */
/* and strip all trailing zeroes. */
if pos('E',!)\==0 then do /*is ! in exponential notation? */
d=digits() /*D is current digs*/
numeric digits d+d%10 /*add ten percent. */
!=o!*j /*recalculate for the lost digit. */
end
!=strip(!,'tail-end',0) /*kill some electrons, strip 0's. */
end /*(above) only 1st letter is used.*/
/*let's perform some housekeeping.*/
if pos('E',!)\==0 then !=strip(!/1,"T",0) /*! in exponential notation?*/
v=5; tz=0
do while v<=n /*calculate # of trailing zeroes. */
tz=tz+n%v
v=v*5
end /*while v≤n*/
!=! || copies(0,tz) /*add some water to rehydrate !. */
/*REXX program computes the factorial of a number, striping trailing 0's*/
numeric digits 200 /*start with two hundred digits. */
parse arg N .; if N=='' then N=0 /*get argument from command line.*/
!=1 /*define factorial produce so far*/
/*═══════════════════════════════════════where the rubber meets the road*/
do j=2 to N /*compute factorial the hard way.*/
old!=! /*save old ! in case of overflow.*/
!=!*j /*multiple old factorial with J.*/
if pos('E',!)\==0 then do /*is ! in exponential notation?*/
d=digits() /*D temporarly stores # digits.*/
numeric digits d+d%10 /*add 10% do digits.*/
!=old!*j /*recalculate for the lost digits*/
end /*IFF ≡ if and only if. [↓] */
if right(!,1)==0 then !=strip(!,,0) /*strip trailing zeroes IFF the*/
end /*j*/ /* [↑] right-most digit is zero.*/
z=0 /*the number of trailing zeroes. */
do v=5 by 0 while v<=N /*calculate # of trailing zeroes.*/
z=z+N%v /*bump Z if multiple power of 5. */
v=v*5 /*calculate the next power of 5. */
end /*while v≤N*/ /* [↑] advance V by ourselves.*/
/*══════════════════════════════════════════════════════════════════════*/
say n'! is ['length(!) "digits]:" /*display # of digits in factorial*/
say /*add some whitespace to output, */
say ! /* ... and display the ! product.*/
!=! || copies(0,z) /*add water to rehydrate the !. */
if z==0 then z='no' /*use gooder English for message.*/
say N'! is ['length(!) " digits with " z ' trailing zeroes]:'
say /*display blank line (whitespace)*/
say ! /* ··· and display the ! product.*/
/*stick a fork in it, we're done.*/