Code that command #1

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Code that command #1

rhombus p 21 Apr 2010 12:49

inspired by this thread, i have come up with a new game/challenge for the ti-83/84 calcs called code that command. basically the idea is to make a program or subroutine that does the same thing that a built in command already does.

this competition will be judged by

• the fact that it does the same thing that the built in command does
• optimization
• Speed
• usability

in honor of this thread, the first challenge will be to code a subroutine that does the same thing that the length() command.

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Last edited on 22 Apr 2010 11:12 by rhombus p Show more

Re: Code that command #1

theUnnamed 21 Apr 2010 14:17

First how should we submit our code?
second unless you are working on the 84 series the only way this is even possible is using some kind of a symbol table which is not provided to basic coders this command would require one to recreate the symbol table for the calculator in a list of some sort which could become huge really fast. so unless you can some how gain access to the symbol table of the calculator this command is crazy hard to implement. on the 84 it is rather easy.

Last edited on 21 Apr 2010 17:56 by theUnnamed Show more

Re: Code that command #1

Weregoose 21 Apr 2010 14:46

inString(Ans+"?"+Ans,Ans,2)-2 for strings not of the form "c₁c₂…c_n?c₁c₂…c_n" and "?" a string of low expected frequency.

Obviously a loop will seal the deal, but there's my one entry.

Re: Code that command #1

theUnnamed 21 Apr 2010 18:33

Using weregoose's idea (although I thought of it independently) and a good understanding about how a good the instring function works i propose that the best possible way to do this is.

:Ans+"GarbageCollectGarbageCollectGarabageCollect1->Str1
:"GarbageCollectGarbageCollectGarabageCollect1->Str2
:instring(Str1,Str2
:while Ans
:Ans->A
:InString(Str1,Str2,Ans+1
:End
:Return A-1

I assume the caclulator is using the Boyer–Moore string search algorithm so more adding GarbageCollect s may run faster or using a more common character in place of 1 or less common in place of GargageCollect

Last edited on 25 Apr 2010 23:37 by theUnnamed Show more

Re: Code that command #1

Chokladkakan 21 Apr 2010 19:31

Well, in terms of speed, I certainly have to disagree; I ran the numbers:

Weregoose's example:

startTmr→T
For(I,1,6E3
"THIS IS A SPEED TEST
inString(Ans+"?"+Ans,Ans,2)-2
End
checkTmr(T

returns 388 seconds.

Your code:

startTmr→T
For(I,1,6E3
"THIS IS A SPEED TEST
Ans+"GarbageCollectGarbageCollectGarabageCollect1->Str1
"GarbageCollectGarbageCollectGarabageCollect1->Str2
instring(Str1,Str2
while Ans
Ans->A
InString(Str1,Str2,A+1)
End
End
checkTmr(T

returns 773 seconds.

And, as a fun comparison (which also makes Weregoose's code look really impressive):

startTmr→T
For(I,1,6E3
"THIS IS A SPEED TEST
length(Ans
End
checkTmr(T

returns 340 seconds.

Edit: not saying I have any better method myself: I absolutely do not. I was just curious of how the both methods performed.

Last edited on 21 Apr 2010 19:32 by Chokladkakan Show more

Re: Code that command #1

Weregoose 21 Apr 2010 20:24

The question mark was added to prevent the miscalculations on the lengths of strings that are merely periodic, e.g., "ABCABC"; if the middle term is removed, it still suffices to measure "ABCDABC" and "ABCABCD" correctly.

Re: Code that command #1

theUnnamed 22 Apr 2010 17:43

Mine was a fully qualified solution weregoose's was not. He said it himself "Obviously a loop will seal the deal." Mine has the loop and has to do a double test of instring to ensure there is no instance of "GarbageCollectGarbageCollectGarabageCollect1" in the string other than the one i put at the end (how ever unlikely that maybe)
and because input is alpha change the 1 to E

Last edited on 22 Apr 2010 17:43 by theUnnamed Show more

Re: Code that command #1

Weregoose 23 Apr 2010 11:01

Mine was a fully qualified solution weregoose's was not. He said it himself "Obviously a loop will seal the deal."

My entire intent was to post a less obvious solution to give others a chance to have fun crafting their loops. But the fact remains that there are strings which your version still wouldn't gauge correctly, which I didn't anticipate. This one is fail-proof:

1
While inString(Str1+"01","0",Ans
Ans+1
End
Ans-2

Last edited on 23 Apr 2010 11:02 by Weregoose Show more

Re: Code that command #1

theUnnamed 25 Apr 2010 17:12

What would mine have not done correctly?
also I didn't know while stored ans that's pretty cool

Last edited on 25 Apr 2010 17:15 by theUnnamed Show more

Re: Code that command #1

Weregoose 25 Apr 2010 18:52

Now explain to me why you think While stores Ans.

Furthermore, I challenge you to write a sample piece of code proving that it does.

Re: Code that command #1

theUnnamed 25 Apr 2010 23:35

Im sorry i got confused about stuff never mind your code works without while storing ans so never mind but your loop runs a way excessive number of times.
BTW made 2 small changes to my original code wasn't thinking when i wrote it. used var instead of ans in InString statement and also had an extra parenthesis in there so i change it

Last edited on 25 Apr 2010 23:44 by theUnnamed Show more

Re: Code that command #1

Weregoose 21 Apr 2010 20:08

i propose the best possible way to do this is.

There are a million satisfied programmers. Try to be the one who is not satisfied, and the only direction you can move is forward.

See what can be done with: inString(Str1+"01","0",X

Re: Code that command #1

Zaetsi 23 Apr 2010 21:25

Um, two things. How and when would we have to have the programs done by? Can it do something like, go through a loop with the command sub(str1, X, 1) adding 1 to X until there's a dim error? What I mean is, can it do whatever however so that it returns the proper length, or does it have to replicate length() exactly?

Re: Code that command #1

rhombus p 27 Apr 2010 17:23

i think Weregoose won this one. his code was very small, optimized and was very fast. good job!

the winning code

1
While inString(Str1+"01","0",Ans
Ans+1
End
Ans-2

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