15 lines
1.4 KiB
Rexx
15 lines
1.4 KiB
Rexx
/*REXX program to show anonymous recursion of a function or subroutine with memoization.*/
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numeric digits 1e6 /*in case the user goes ka-razy with X.*/
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parse arg x . /*obtain the optional argument from CL.*/
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if x=='' | x=="," then x=12 /*Not specified? Then use the default.*/
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@.=.; @.0=0; @.1=1 /*used to implement memoization for FIB*/
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w=length(x) /*W: used for formatting the output. */
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do j=0 for x+1 /*use the argument as an upper limit.*/
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say 'fibonacci('right(j, w)") =" fib(j)
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end /*j*/ /* [↑] show Fibonacci sequence: 0 ──► X*/
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exit /*stick a fork in it, we're all done. */
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/*──────────────────────────────────────────────────────────────────────────────────────*/
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fib: procedure expose @.; arg z; if z>=0 then return .(z)
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say "***error*** argument can't be negative."; exit
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.: procedure expose @.; arg #; if @.#\==. then return @.#; @.#=.(#-1)+.(#-2); return @.#
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