Rosetta Code

Mutual recursion: Difference between revisions

Page Discussion

Mutual recursion (view source)

Revision as of 21:26, 17 May 2012

3,396 bytes added ,  12 years ago
→‎{{header|REXX}}: added version 2, changed the format of the output. -- ~~~~
(Made code Forth200x compliant)
(→‎{{header|REXX}}: added version 2, changed the format of the output. -- ~~~~)
Line 1,435:
 
=={{header|REXX}}==
===version 1===
<lang rexx>/*REXX program to showshows mutual recursion. (via Hofstadter Male & Female seq)*/
arg limit .; if limit='' then limit=40
arg lim .; if lim='' then lim=40; pad=left('',20)
do j=0 to limit
 
say 'F('right(j,2)")="right(F(j),9) ' M('right(j,2)")="right(M(j),9)
do j=0 to lim; jj=Jw(j); ff=F(j); mm=M(j)
say pad 'F('jj") =" Jw(ff) pad 'M('jj") =" Jw(mm) /*display nicely.*/
end
 
exit
/*─────────────────────────────────────F, M, & MJw subroutines─────────────subroutines────────────*/
F: procedure; parse arg n; if n==0 then return 1; return n-M(F(n-1))
M: procedure; parse arg n; if n==0 then return 0; return n-F(M(n-1))</lang>
Jw: return right(arg(1),length(lim)) /*right justifies # for nice look*/</lang>
'''output''' (using the default of 40):
<pre style="height:30ex;overflow:scroll">
F( 0) = 1 1 M( 0)= M( 0) = 0
F( 1) = 1 1 M( 1)= M( 1) = 0
F( 2) = 2 2 M( 2)= M( 2) = 1
F( 3) = 2 2 M( 3)= M( 3) = 2
F( 4) = 3 3 M( 4)= M( 4) = 2
F( 5) = 3 3 M( 5)= M( 5) = 3
F( 6) = 4 4 M( 6)= M( 6) = 4
F( 7) = 5 5 M( 7)= M( 7) = 4
F( 8) = 5 5 M( 8)= M( 8) = 5
F( 9) = 6 6 M( 9)= M( 9) = 6
F(10) = 6 6 M(10)= M(10) = 6
F(11) = 7 7 M(11)= M(11) = 7
F(12) = 8 8 M(12)= M(12) = 7
F(13) = 8 8 M(13)= M(13) = 8
F(14) = 9 9 M(14)= M(14) = 9
F(15) = 9 9 M(15)= M(15) = 9
F(16) = 10 10 M(16)= M(16) = 10
F(17) = 11 11 M(17)= M(17) = 11
F(18) = 11 11 M(18)= M(18) = 11
F(19) = 12 12 M(19)= M(19) = 12
F(20) = 13 13 M(20)= M(20) = 12
F(21) = 13 13 M(21)= M(21) = 13
F(22) = 14 14 M(22)= M(22) = 14
F(23) = 14 14 M(23)= M(23) = 14
F(24) = 15 15 M(24)= M(24) = 15
F(25) = 16 16 M(25)= M(25) = 16
F(26) = 16 16 M(26)= M(26) = 16
F(27) = 17 17 M(27)= M(27) = 17
F(28) = 17 17 M(28)= M(28) = 17
F(29) = 18 18 M(29)= M(29) = 18
F(30) = 19 19 M(30)= M(30) = 19
F(31) = 19 19 M(31)= M(31) = 19
F(32) = 20 20 M(32)= M(32) = 20
F(33) = 21 21 M(33)= M(33) = 20
F(34) = 21 21 M(34)= M(34) = 21
F(35) = 22 22 M(35)= M(35) = 22
F(36) = 22 22 M(36)= M(36) = 22
F(37) = 23 23 M(37)= M(37) = 23
F(38) = 24 24 M(38)= M(38) = 24
F(39) = 24 24 M(39)= M(39) = 24
F(40) = 25 25 M(40)= M(40) = 25
</pre>
===version 2===
This version of the REXX program uses memoization as well as a horizontal output format.
<br><br>The optimization due to memoization is faster by many orders of magnitude.
<lang rexx>/*REXX program shows mutual recursion (via Hofstadter Male & Female seq)*/
arg lim .;if lim='' then lim=99; hm.=; hm.0=0; hf.=; hf.0=1; Js=; Fs=; Ms=
 
do j=0 to lim; ff=F(j); mm=M(j)
Js=Js jW(j); Fs=Fs jw(ff); Ms=Ms jW(mm)
end
 
say 'Js='strip(Js)
say 'Fs='strip(Fs)
say 'Ms='strip(Ms)
exit
/*─────────────────────────────────────F, M, Jw subroutines────────────*/
F: procedure expose hm. hf.;parse arg n;if hf.n=='' then hf.n=n-M(F(n-1))
return hf.n /*Hofstadter seq uses memoization*/
 
M: procedure expose hm. hf.;parse arg n;if hm.n=='' then hm.n=n-F(M(n-1))
return hm.n /*Hofstadter seq uses memoization*/
 
Jw: return right(arg(1),length(lim)) /*right justifies # for nice look*/</lang>
'''output''' (using the default of 99):
<pre style="height:15ex;overflow:scroll">
Js=0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99
Fs=1 1 2 2 3 3 4 5 5 6 6 7 8 8 9 9 10 11 11 12 13 13 14 14 15 16 16 17 17 18 19 19 20 21 21 22 22 23 24 24 25 25 26 27 27 28 29 29 30 30 31 32 32 33 34 34 35 35 36 37 37 38 38 39 40 40 41 42 42 43 43 44 45 45 46 46 47 48 48 49 50 50 51 51 52 53 53 54 55 55 56 56 57 58 58 59 59 60 61 61
Ms=0 0 1 2 2 3 4 4 5 6 6 7 7 8 9 9 10 11 11 12 12 13 14 14 15 16 16 17 17 18 19 19 20 20 21 22 22 23 24 24 25 25 26 27 27 28 29 29 30 30 31 32 32 33 33 34 35 35 36 37 37 38 38 39 40 40 41 42 42 43 43 44 45 45 46 46 47 48 48 49 50 50 51 51 52 53 53 54 54 55 56 56 57 58 58 59 59 60 61 61
</pre>
 
Retrieved from "https://rosettacode.org/wiki/Special:MobileDiff/106614"