Permutations: Difference between revisions

<br><br>It doesn't have the formatting capabilities of the REXX version 1, &nbsp; nor can it handle taking &nbsp; '''X''' &nbsp; items taken &nbsp; '''Y''' &nbsp; at-a-time.

<lang rexx>/*REXX program showsdisplays permutations of N number of objects (1, 2, 3, ... ···). */

parse arg n .; if n=='' | n=="," then n=3 /*Not specified? Then /*populateuse the first permutationdefault. */

do pop=1 for n; @.pop=pop ; end; call tell n /* [↓] populate the first permutation.*/

do pop=1 while nextPerm(for n,0); call tell n @.pop=pop ; end /*pop */; call tell n

nextPermnPerm: procedure expose @.; parse arg n,i; nm=n-1

do j=i+1 while doj<n; k=nm parse byvalue -1 @.j for nm;@.n kp=k+1;with @.n if @.k<@.kpj; then do; in=kn-1; end leave; end/*j*/

if i==0 then endreturn /*k*/0

do j=i+1 while j<n; parse value @.jm @.n i with @.ni @.j; n=n-1m

return end /*j*/1

tell: procedure expose @.; _=; do j=1 for arg(1); _=_ @.j; end; say _; return</lang>

'''output''' &nbsp; when using the default input: