18 lines
1.4 KiB
Rexx
18 lines
1.4 KiB
Rexx
/*REXX program shows mutual recursion (via the Hofstadter Male and Female sequences). */
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/*───────────────── If LIM is negative, a single result is shown for the abs(lim) entry.*/
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parse arg lim .; if lim=='' then lim= 99; aLim= abs(lim)
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w= length(aLim); $m.=.; $m.0= 0; $f.=.; $f.0= 1; Js=; Fs=; Ms=
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do j=0 for aLim+1; call F(J); call M(j)
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if lim<0 then iterate
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Js= Js right(j, w); Fs= Fs right($f.j, w); Ms= Ms right($m.j, w)
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end /*j*/
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if lim>0 then say 'Js=' Js; else say 'J('aLim")=" right( aLim, w)
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if lim>0 then say 'Fs=' Fs; else say 'F('aLim")=" right($f.aLim, w)
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if lim>0 then say 'Ms=' Ms; else say 'M('aLim")=" right($m.aLIM, w)
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exit /*stick a fork in it, we're all done. */
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/*──────────────────────────────────────────────────────────────────────────────────────*/
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F: procedure expose $m. $f.; parse arg n; if $f.n==. then $f.n= n-M(F(n-1)); return $f.n
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M: procedure expose $m. $f.; parse arg n; if $m.n==. then $m.n= n-F(M(n-1)); return $m.n
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