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Multiplicative order: Difference between revisions
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→{{header|REXX}}: added whitespace, used a template for an output section.
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=={{header|REXX}}==
<lang rexx>/*REXX pgm computes multiplicative order of a minimum integer N such that a^n mod m≡1*/
wa= 0; wm= 0 /* ═a═ ══m══ */
@.=.; @.1= 3 10
@.2= 37 1000
@.3= 37 10000
@.4= 37 3343
@.5= 37 3344
@.6= 2 1000
pad= left('', 9)
d=
do w=1 for 2 /*when W≡1, find max widths of A and M.*/
do j=1 while @.j\==.; parse var @.j a . 1 r m , n
if w==1 then do; wa= max(wa, length(a) ); wm= max(wm, length(m) );
if m//a==0 then n= ' [solution not possible]' /*test co─prime for A and B. */
numeric digits d /*start with 100 decimal digits. */
if n=='' then do n= 2;
parse var p 'E' _ /*try to extract the exponent from P. */
if _\=='' then do; numeric digits _+d /*bump the decimal digs.*/
p=r*a /*recalculate integer P.*/
end
if p//m==1 then leave /*now, perform the
r= p
end /*n*/ /* [↑] // is really ÷ remainder.*/
say pad 'a=' right(a,wa) pad "m=" right(m,wm) pad 'multiplicative order:' n
end /*j*/
end /*w*/ /*stick a fork in it, we're all done. */</lang>
<pre>
a= 3 m= 10 multiplicative order: 4
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