Hofstadter Figure-Figure sequences: Difference between revisions
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(→{{header|REXX}}: re-wrote the subroutines and verification routine. -- ~~~~) |
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=={{header|REXX}}== |
=={{header|REXX}}== |
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This REXX example makes use of spare arrays. |
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<lang rexx>/*REXX pgm to calculate & verify the Hofstadter Figure-Figure sequences.*/ |
<lang rexx>/*REXX pgm to calculate & verify the Hofstadter Figure-Figure sequences.*/ |
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parse arg x highV . /*obtain any C.L. specifications.*/ |
parse arg x highV . /*obtain any C.L. specifications.*/ |
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if x<0 then low=abs(x) /*only show a single │X│ value.*/ |
if x<0 then low=abs(x) /*only show a single │X│ value.*/ |
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r.=0; r.1=1; rr.=r.; rr.1=1 /*initialize the R and RR arrays.*/ |
r.=0; r.1=1; rr.=r.; rr.1=1 /*initialize the R and RR arrays.*/ |
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s.=0; s.1=2; ss.=s.; ss.2=1 /* " |
s.=0; s.1=2; ss.=s.; ss.2=1 /* " ? S " SS " .*/ |
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errs=0 |
errs=0 |
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do i=low to abs(x) /*show first X values of R & S */ |
do i=low to abs(x) /*show first X values of R & S */ |
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both.=0 /*initialize the BOTH array. */ |
both.=0 /*initialize the BOTH array. */ |
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/*build list of 1st 40 R values.*/ |
/*build list of 1st 40 R values.*/ |
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do m=1 for 40; r=ffr(m) /*calculate 1st 40 R |
do m=1 for 40; r=ffr(m) /*calculate 1st 40 R values.*/ |
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both.r=1 /*build the BOTH array. */ |
both.r=1 /*build the BOTH array. */ |
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end /*m*/ |
end /*m*/ |
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/*build list of 1st 960 S values.*/ |
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do n=1 for 960; s=ffs(n) |
do n=1 for 960; s=ffs(n) /*calculate 1st 960 S values.*/ |
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if both.s then call sayErr 'duplicate number in R and S lists:' s |
if both.s then call sayErr 'duplicate number in R and S lists:' s |
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both.s=1 |
both.s=1 /*add to the BOTH array. */ |
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end /*n*/ |
end /*n*/ |
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/*verify presence and uniqueness.*/ |
/*verify presence and uniqueness.*/ |
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do v=1 for highV |
do v=1 for highV /*verify all 1 ≤ # ≤ 1k present.*/ |
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if \both.v then call sayErr 'missing R |
if \both.v then call sayErr 'missing R │ S:' v |
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end /*v*/ |
end /*v*/ |
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say |
say |
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@v='verification'; @i=" [inclusive]." /*shortcuts to shorten prog width*/ |
@v='verification'; @i=" [inclusive]." /*shortcuts to shorten prog width*/ |
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ffr: procedure expose r. s. rr. ss.; parse arg n |
ffr: procedure expose r. s. rr. ss.; parse arg n |
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if r.n\==0 then return r.n /*Defined? Then return the value.*/ |
if r.n\==0 then return r.n /*Defined? Then return the value.*/ |
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_ |
_=ffr(n-1)+ffs(n-1) /*calculate the FFR value. */ |
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r.n |
r.n=_; rr._=1 /*assign the value to R and RR.*/ |
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return _ /*return the value to the invoker*/ |
return _ /*return the value to the invoker*/ |
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/*──────────────────────────────────FFS subroutine──────────────────────*/ |
/*──────────────────────────────────FFS subroutine──────────────────────*/ |
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ffs: |
ffs: procedure expose r. s. rr. ss.; parse arg n |
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do k=1 for n while s.n==0 /*search for not null R │ S num.*/ |
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if s.k\==0 & ffr(k)\==0 then iterate |
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km=k-1; _=s.km+1 /*the next SS number, possibly.*/ |
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_=_+rr._ /*maybe adjust for the FRR num.*/ |
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s.k=_; ss._=1 /*define couple of FFS numbers.*/ |
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end /*k*/ |
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return s.n /*return the value to the invoker*/ |
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return s.n /*return the value to the invoker*/ |
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/*──────────────────────────────────SAYERR subroutine───────────────────*/ |
/*──────────────────────────────────SAYERR subroutine───────────────────*/ |
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sayErr: errs=errs+1; say; say '***error***!'; say; say arg(1); say; return</lang> |
sayErr: errs=errs+1; say; say '***error***!'; say; say arg(1); say; return</lang> |
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