Check if int

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Check if int

Erik (guest) 08 May 2012 22:36

In math class, we were given an extra credit problem on our test, asking what positive integers will never fit the form of a^2+b^2=c^2 where a, b, and c are integral.
I wrote a program to solve it
my code was as follows:

Define xc()=
Prgm
Local a
While a<100 //I took a guess and said that if one leg is 2, the other will be less then 100
   Disp a^2+2^2
   Disp a
EndWhile
EndPrgm

I watched as the numbers scolled through, and attempted to see if there were 2 ints in a row. It worked, but I was hoping if anyone knew of a way to include an if statement with something that returned the number a was at, and the answer only when it was an int.

A continuation of this would be to do

Define xc()=
Prgm
Local a
local b
While b<100
 While a<100 
   Disp sqrt(a^2+b^2)
   Disp a
 EndWhile
EndWhile
EndPrgm

while checking for ints.

Thank you

Re: Check if int

Wolfgang47 08 May 2012 22:45

That's awesome. I don't know N-Spire language, bu that is cool.
I also love it when I am taking a math test and there's a problem type that we never went over, & I am like, "Well, we never learned how to do this, but, haha! I know how to write a program to do it for me".

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—Wolfgang

Erik (guest) 08 May 2012 22:49

Its a great feeling. I'm in geometry, and this is the first program I wrote on-site that helped this year, but last year I did it couple times for probability problems.

BlakPilar 08 May 2012 22:53

Hmm… What do you mean "if it's an int?" As in, there are no decimals? If that's the case, check if the NSpire has an fPart command. If it does, fPart(NUMBER)=0 will be true if there are no decimals. If there is no fPart command, then round(NUMBER,0)=NUMBER will do the same thing.

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Projects: BexIDE (hold), Hadean.NET, Legend of Zelda: Link to the Future

blue_bear_94 08 May 2012 23:14

For a moment I thought you were programming for the 89.

Define xc()=
Prgm
Local a,b,c
For b,1,100
 For a,1,100
   sqrt(a^2+b^2)→c
   Disp a,",",b,":",c
   If 0=fPart(c) Then
   Pause "Int"
   Else
   Pause "Not int"
   EndIf
 EndFor
EndFor
EndPrgm

Also, slap yourself.

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Last edited on 08 May 2012 23:27 by blue_bear_94 Show more

Erik (guest) 08 May 2012 23:31

Thank you for giving a practical example. What does the "Pause" method do?

Also, that last part was uncalled for. All I had done with whatever language the Nspire is lets us write in before this was combining arguments, randInts, goto, and Disp.

I was in the middle of a test, realized For had different syntax then java, and While is the simplest loop. I apologize for not writing clean, optimized code before learning the language.

And I got it, thanks all.

Erik (guest) 08 May 2012 23:16

What I am trying to do is to find out what returns an integer, and what numbers do not. Sounds like I need fPart.
thanks.
Ill try it, and post when I figure it out

blue_bear_94 08 May 2012 23:26

Exactly what I posted.

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Sunrise 3 Progress: 30%
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Erik (guest) 08 May 2012 23:36

Not exactly what you posted.
I am trying to write code that gives me ints that never follow the conditions.
Also, I hadn't refreshed the page, and therefor hadn't seen your post when I responded…

blue_bear_94 08 May 2012 23:47

Then you'd have

Define xc()=
Prgm
Local a,b
For b,1,100
 For a,1,100
   If 0≠fPart(sqrt(a^2+b^2))
   Disp a,",",b
 EndFor
EndFor
EndPrgm

Also, I realized that the Pause command didn't exist on the Nspire. I slapped myself.

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Sunrise 3 Progress: 30%
Size: around 20 KB, not including the save lists and in-game RAM.

Last edited on 08 May 2012 23:48 by blue_bear_94 Show more

BlakPilar 10 May 2012 01:01

blue_bear, please stop being so rude. Not everyone knows exactly what to do, which is why they come and ask for help. There's no need to degrade them or be forceful.

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Projects: BexIDE (hold), Hadean.NET, Legend of Zelda: Link to the Future

fredvanner (guest) 26 Oct 2012 12:53

Sets of numbers (a, b, c) such that a²+b²=c² are called Pythagorian triples (e.g. see Wikipedia).
It can be proved that all PTs are of the form:
k*(m²-n²), k*(2mn), k*(m²+n²), k, m, n integers, m>n.
It follows that, if n>1 is odd, then (n, (n²-1)/2, (n²+1)/2) is a PT, and
if n>2 is even, then (n, (n/2)²-1, (n/2)²+1) is a PT.
So 1 and 2 are the only integers that are not in any PT!

FREDVANNER

bsch2734 26 Oct 2012 17:22

@fredvanner:
Pease whatch the dates when posting. This thread as been dead for almost 6 months.

TheNlightenedOne (guest) 08 Mar 2013 01:19

Well, If you want to check if something is an int, compare it with its rounded value. Probably not optimized, but it works.