Divisible Number Program Help

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Summary:

I has a problem and I need your ideas and help to fix.

Divisible Number Program Help

Keynah 09 Jun 2012 02:43

I am currently making a program that takes two numbers, A and B, and find the divisible numbers between them both.
Ex. 40 and 20, 1,2,4,10,etc.

To accomplish this task I need some help,

One element of this program is taking the two numbers dividing them by a common integer then storing each number after division to a list

:1→N
:1→G
{0,0,0}→q      This stores (0,0,0) to a the variable q, but also makes it a list
{0,0,0}→r
:Input A        Input two numbers
:Input B      
:
:A/n→q[g]         Division by common number, Q and R are lists with g being the position the divided number is being stored.
:B/n→r[g]
:

Now the really tricky part is here.

How do i cross check each of the lists to find a common number besides using SortA and SortD since they have limited use?

Ex.
:List Q {5,6,7}
:List R {6,8,9}
:
:
: Using SortA or SortD would not work to cross check the lists even though there is a common number.

*SideNote I typed this all by hand so if the coding looks funky thats my bad*

Please comment to help me in TI-89 Format with somewhat of an explaintion of your coding.
-Thanks Keynah

(I will check this in 2-3 days , 6/8/2012)

Last edited on 09 Jun 2012 16:00 by Keynah Show more

Re: Divisible Number Program Help

7HQR 10 Jun 2012 03:46

I do not know the TI-89 language but I can give you the general outline of how I would write it with the 83

For(A,1,*first#*
If *first#* is divisible by A
store A to list1
End
For(A,1,*second#*
If *second#* is divisible by A
store A to list2
End
For(A,1,*length of list1*
If list1(A) is in List 2
store # to list3
End
Clear lists1and2
list3 has your common divisibles

Sorry if that doesn't help really because I don't know the language

Re: Divisible Number Program Help

Xeda Elnara 10 Jun 2012 11:16

Okay, I have a crazy idea, I don't have my TI-89 right here and I won't have internet after today for a while, buut here goes…

Input A
Input B
gcd(A,B)→C      ;All you have to do is find all the factors to this
{C}→q
1→G
iPart(sqrt(C))→D
While D>1
While fPArt(C/D)       ;I would have just used mod(), but I am not sure how the TI-89 handles mod 1.
D-1→D
EndWhile
D→q[G]
G+1→G
C/D→q[G]
G+1→G
EndWhile
SortA(q)

I've never had much practice with 89 BASIC, so some of the syntax might be wrong and I haven't tested the code yet, but hopefully it works. I am not sure if factor() can be used on integers, but if it can, use it.

In case you don't get why all you need to do is factor the GCD of the two numbers, think about it— the Greatest Common Divisor has all the mutual factors. If you do A/GCD(A,B) and B/GCD(A,B), they are by definition relatively prime (so they have no common factors). As a side note for the curious, the code I provided is not even close to polynomial time speed, but GCD itself is a polynomial time algorithm (and quite simple, too).

I like math >.>

---

Z80 Assembly>English>TI-BASIC>Python>French>C>0

Last edited on 10 Jun 2012 20:07 by Weregoose Show more

Re: Divisible Number Program Help

blue_bear_94 11 Jun 2012 01:24

SortA does not use parentheses. Also, note that variable names would be converted into lowercase on execution.

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

George Litauszky (guest) 30 Jul 2012 06:11

:List P {5,6,7}
:List Q {6,8,9}

If you convert List P to string, you can search in it with the inString command. If the result is not 0, it's a new common divisor.

common()
Prgm
Local pstr,qsi,n,nr
string(p)->pstr
dim(q)->qsi
0->nr
newList(qsi)->res
For n,1,qsi
If inString(pstr,string(q[n]))<>0 Then
nr+1->nr
q[n]->res[nr]
EndIf
EndFor
left(res,nr)->res
Disp res
EndPrgm

How can I insert here a formatted text?

George Litauszky (guest) 01 Aug 2012 20:07

BTW1:
I converted Xeda's code to 68k Basic format. Despite any syntax and a program structure error the program's logic is correct and demontstrate the short, fast and deliberate programming opposite the brute force method, congratulations. :)

xeda(a,b)                     © a, b numbers= parameters
Prgm
 Local c,d,g
 gcd(a,b)->c
 newList(c)->q
 1->g
 iPart(sqr(c))->d
 While d>0                     © While d>1={}(empty list output) if a=2 and b=4 for ex.
  While mod(c/d,1)>0           © We need add a condition in 68k basic.
   d-1->d
  EndWhile
  d->q[g]
  g+1->g
  If c/d ≠ d Then              © If block: for the sake of number
   c/d->q[g]                   © duplicating in the q list.
  EndIf
  d-1->d                       © Without this, infinite loop.                        
 EndWhile
 left(q,g-1)->q                © q list without zeros.                
 SortA q
 disp q
EndPrgm

BTW2:
"I am not sure if factor() can be used on integers, but if it can, use it."
Yes. If the 2 numbers are a=20 and b=40 for example, the shortest way to calculate all the common divisors without programming is this:

factor(gcd(20,40)) = 2^2*5

So the divisors are: 2, 2^2, 2*5, 2^2*5.
I like this text formatting. ;)

George Litauszky (guest) 01 Aug 2012 20:26

And 5 of course.

George Litauszky (guest) 01 Aug 2012 22:23

Because I'm only a guest here, I can't edit my posts. Here is a typo in prg list above:

  If c/d ≠ d Then              © If block: for the sake of number
   c/d->q[g]                   © duplicating in the q list.
   g+1->g                      ©  <<<- This is the missing line.
  EndIf