How to get numerator/denominator of fractions seperately in 68k TI-BASIC?

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How to get numerator/denominator of fractions seperately in 68k TI-BASIC?

LoganDark 20 Oct 2017 10:39

For example, if I have the expression 2/3, I want to get 2 and 3 as seperate numbers. Can I do that in 68k TI-BASIC?

Re: How to get numerator/denominator of fractions seperately in 68k TI-BASIC?

Myles_Zadok 20 Oct 2017 23:56

I don't know where Battlesquid is at, but he'll be around to help you shortly.

Re: How to get numerator/denominator of fractions seperately in 68k TI-BASIC?

Step7 21 Oct 2017 03:48

Convert the number variable containing your fraction to a string. Use inString to return position of "/" in that string then isolate numerator and denominator using Left( and Right( based on the returned position. You may want to handle circumstance where input isn't a fraction. Shout if you need code example

Re: How to get numerator/denominator of fractions seperately in 68k TI-BASIC?

Battlesquid 21 Oct 2017 05:09

Assuming that the fraction is in a variable named frac:

setMode("Exact/Approx","EXACT")
string(frac)&"/1"→str
inString(str,"/")→pos
dim(str)-pos→pos2
expr(mid(str,1,pos-1))→num
expr(right(str,pos2))→denom

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Last edited on 21 Oct 2017 15:15 by Battlesquid Show more

Re: How to get numerator/denominator of fractions seperately in 68k TI-BASIC?

Step7 21 Oct 2017 06:02

Close ;)

Re: How to get numerator/denominator of fractions seperately in 68k TI-BASIC?

Battlesquid 21 Oct 2017 06:09

I usually make overly complicated programs. I think I know how to incorporate right() into the code, but making this code was way more fun :P

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Last edited on 21 Oct 2017 06:09 by Battlesquid Show more

Re: How to get numerator/denominator of fractions seperately in 68k TI-BASIC?

Step7 21 Oct 2017 06:32

Definitely fun.. (I might have a go at a code example for this after some sleep :o) Typo on last line tho? Should that be pos2 not pos?

Re: How to get numerator/denominator of fractions seperately in 68k TI-BASIC?

Battlesquid 21 Oct 2017 14:43

Fixed that typo, thanks for pointing that out :)

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Re: How to get numerator/denominator of fractions seperately in 68k TI-BASIC?

Step7 21 Oct 2017 15:00

NP, should read pos2+1 though? :p.

Suggest..

string(frac)&"/1"→str

..to avoid Domain Error when handling fractions that resolve to whole numbers e.g 3/1, 16/16.. code will return Denom of 1.

Last three lines could be boiled down to 2 and no need for variables, but will leave that for now as I see OP has found in-built functions to the job a whole lot better:)

Re: How to get numerator/denominator of fractions seperately in 68k TI-BASIC?

Battlesquid 21 Oct 2017 15:14

Woah, never saw that solution, great job Step7! I decided to put everything in variables because it would be easier to read.

Also, the code works with the current expr(right(str,pos2))→denom, adding one would increase the value of the denominator, which would be inaccurate, and putting the one inside the right() command yields a syntax error.

And I never realized that there were commands that separate the numerator and denominator. Like I said, I always make overly complicated programs :)

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Re: How to get numerator/denominator of fractions seperately in 68k TI-BASIC?

Step7 21 Oct 2017 15:55

I was suggesting adding 1 to Pos2 (not resulting Denom), to skip one place right of the "/", think as you have it will get "/3" returned and error on evaluating that expression?

expr(right(str,pos2+1))→denom

Re: How to get numerator/denominator of fractions seperately in 68k TI-BASIC?

Battlesquid 21 Oct 2017 16:18

Yep, I still get a syntax error. The only way I could position the 1 was to add it outside the parenthesis, and that just added 1 to the value of the denominator. I tried out using 2/3, and it worked perfectly…

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Re: How to get numerator/denominator of fractions seperately in 68k TI-BASIC?

Step7 21 Oct 2017 16:31

Think I've muddled the code I was thinking of with what you've listed.

Try..

setMode("Exact/Approx","EXACT")
string(frac)&"/1"→str
inString(str,"/")→pos
expr(left(str,pos-1))→num
expr(right(str,pos+1))→denom

Re: How to get numerator/denominator of fractions seperately in 68k TI-BASIC?

Battlesquid 21 Oct 2017 17:36

Yep, that works! Great job on the optimization :)

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Re: How to get numerator/denominator of fractions seperately in 68k TI-BASIC?

LoganDark 21 Oct 2017 14:09

2/3→frac
getNum(frac) © 2
getDenom(frac) © 3

Wiki pages please? I honestly don't know how to fill out the command template.

Re: How to get numerator/denominator of fractions seperately in 68k TI-BASIC?

Step7 21 Oct 2017 14:35

Nice work :) works with unity denominators too, which squid's code won't (domain errors for 3/1, 16/16).

+1 on TO DO:
tibasicdev•wikidot•com/68k:getdenom
tibasicdev•wikidot•com/68k:getnum

I have a similar requirement to extract powers from expressions like 2².5⁵. Squid's code could be modified to yield those, but is there built in functions to do this also? Will start a new thread if no answers here..

Last edited on 21 Oct 2017 15:01 by Step7 Show more