Re: TI85 Concatenating numbers/Numbers -> Strng

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Re: TI85 Concatenating numbers/Numbers -> Strng

In <MmZH9a200YUz0ju0c0@andrew.cmu.edu>, Jonathan Todd Samuel
<jsamuel+@andrew.cmu.edu> writes:


>Real-to-String/String-to-Real Modules
>-------------------------------------
>By Jon Niehof and Jason Wenger
>------------------------------




The linear regression trick for number-to-$tring conversion needs to be
modified for the TI-83, but the principle is more or less the same (as on
the 85) -- in practice, it needs to be stated thusly:


  -167.12=A                  ; e.g. a real number to convert...
  {0,1}=L5:{A,A}=L6
  LinReg(ax+b) L5,L6,Y0      ; resulting Y0 equation=0X+(-167.12)
  Equ>String(Y0,Str0
  sub(Str0,4,length(Str0)-3  ; strip leading "0X+" from Str0
  Ans=Str0                   ; Str0="-167.12"


You said that one should avoid all "->" operators in the routine, but it
seems labored not to abbreviate the last two lines as:
  sub(Str0,4,length(Str0)-3)=Str0
The truth is, we're in $tringland from LinReg onward (derivation of the Y0
equation); it seems pretty clear to me that Y VARS are all stored
internally as strings.


Anyway, the kludge works -- amazing but true.  Very clever.  Only problem
is, in the middle of a long program the TI-83 interprets this code and then
insists on graphing the damn equation!  A neat horizontal line, naturally.
Which isn't exactly what I had in mind.  How the devil do I perform the
calc without triggering a graph?
References: