I just recieved my Ti-81 in the mail today. One of the first things I do with my calculators, is make a primes generator using this code:

Code:
```ClrHome Prompt N For(A,1,N,2)  For(B,3,A-1,2)   If fPart(A/B)=0   A->B  End If B=A Disp A End Pause```

But to my suprise, the For( loop isn't present in this model and neither is Prompt. I tried to do it with Lbl and Goto but it didn't work.
This is almost a ritual for me, and it would be nice if I could get some working code for this Historical Calculator.

Edit1: If this helps the Program menu is this:

Code:
```CTL: 1:Lbl 2:Goto 3:If 4:IS>( 5:DS<( 6:Pause 7:End 8:Stop I/O: 1:Disp 2:Input 3:DispHome 4:DispGraph 5:ClrHome EXEC: //this is just: N:Prgm1-Ɵ ```
I don't know if this works, but here's a straightforward translation from reading the manual:
Code:
```ClrHome Input N 1→A Lbl O  2→B  Goto E  Lbl I   If FPart (A/B)=0    A→B   B+1→B   Lbl E  IS>(B,A-1)   Goto I  If B=A   Disp A  A+1→A IS>(A,N)  Goto O Pause```

Edit: Fixed OOO.
I believe I made changes to the code that should make it usable on the TI 81, though I'm not sure because I don't have one myself. From what I understand you just wanted one that does the same thing but is made with labels and without using the prompt command, so here is one I made that seems to be working with only adding the input command (which I believe functions the same):

Code:
```ClrHome Input "N?-",N ~1->A Lbl A A+2->A If (A>N) Goto D 1->B Lbl B B+2->B If (B>=A-1) Goto C If (fPart(A/B)=0) A->B Goto B Lbl C If (B=A) Disp A Goto A Lbl D Pause ```
jacobly wrote:
I don't know if this works, but here's a straightforward translation from reading the manual:
Code:
```ClrHome Input N 1→A Lbl O  3→B  Lbl I   If 0=FPart A/B:A→B   B+1→B  IS>(B,A-1):Goto I  If B=A:Disp A  A+1→A IS>(A,N):Goto O Pause```

you can't type : on the Ti-81, but, I Tried it on the Ti-83+ I have and it didn't work anyway. I really do appreciate your help tho!

bdoggamer wrote:
I believe I made changes to the code that should make it usable on the TI 81, though I'm not sure because I don't have one myself. From what I understand you just wanted one that does the same thing but is made with labels and without using the prompt command, so here is one I made that seems to be working with only adding the input command (which I believe functions the same):

Code:
```ClrHome Input "N?-",N ~1->A Lbl A A+2->A If (A>N) Goto D 1->B Lbl B B+2->B If (B>=A-1) Goto C If (fPart(A/B)=0) A->B Goto B Lbl C If (B=A) Disp A Goto A Lbl D Pause```

This does work. I had to change the code to:

Code:
```Input N ~1->A Lbl A A+2->A If (A>N) Goto D 1->B Lbl B B+2->B If (B>=A-1) Goto C If (FPart (A/B)=0) A->B Goto B Lbl C If (B=A) Disp A Goto A Lbl D Pause ```

just some minor tweaks. It doesn't look like the

Code:
`Input`
command doesn't support two arguments, only one.

Code:
`fPart(`
used to be:
Code:
`FPart `
The TI-81's programming is very crude compared to that of the later models.

The 81 doesn't have “:”, so just start the next piece of code on the next line, which works exactly the same as having a “:” in the middle of the line.
jacobly wrote:
I don't know if this works, but here's a straightforward translation from reading the manual:
Code:
```ClrHome Input N 1→A Lbl O  3→B  Lbl I   If (FPart A/B)=0    A→B   B+1→B  IS>(B,A-1)   Goto I  If B=A   Disp A  A+1→A IS>(A,N)  Goto O Pause```

Edit: Fixed OOO.

slight syntax thingy is wrong:

Code:
``` If (FPart A/B)=0 ```

Should be

Code:
``` If (FPart (A/B))=0 ```

I think this is because FPart on the Ti-81 Doesn't read operations unless told to do so

It does work when this is quickly fixed

Edit: This version of the code does not output primes before 5
jacobly, is there a way to fix this?

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