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From: Sandrus on 25 Sep 2006 09:11
Hi. My teacher gave us a program to do factorial (n!).
But it does not work fine... it always give -12 as resoult.
what do i have to do?
i'm not shure but i could have misread 1 in i or viceversa from the
blackboard. Will you help me?

and please, can anyone explain in a simple way the function of DO?

Here the program is

PROGRAM fattoriale
IMPLICIT NONE
INTEGER :: n, nfatt, i
WRITE(*,*) 'Inserisci un numero'
READ(*,*) n
nfatt=i
DO i = 1,n
END DO
WRITE(*,*) nfatt
STOP
END PROGRAM fattoriale


From: David Flower on 25 Sep 2006 09:30

Sandrus wrote:
> Hi. My teacher gave us a program to do factorial (n!).
> But it does not work fine... it always give -12 as resoult.
> what do i have to do?
> i'm not shure but i could have misread 1 in i or viceversa from the
> blackboard. Will you help me?
>
> and please, can anyone explain in a simple way the function of DO?
>
> Here the program is
>
> PROGRAM fattoriale
> IMPLICIT NONE
> INTEGER :: n, nfatt, i
> WRITE(*,*) 'Inserisci un numero'
> READ(*,*) n
> nfatt=i
(Should read nfatt = 1)
> DO i = 1,n
(Something missing here, left as an exercise to the student!)
> END DO
> WRITE(*,*) nfatt
> STOP
> END PROGRAM fattoriale

Dave Flower

From: beliavsky on 25 Sep 2006 09:34
Sandrus wrote:
> Hi. My teacher gave us a program to do factorial (n!).
> But it does not work fine... it always give -12 as resoult.
> what do i have to do?
> i'm not shure but i could have misread 1 in i or viceversa from the
> blackboard. Will you help me?
>
> and please, can anyone explain in a simple way the function of DO?

Any Fortran textbook or tutorial (links are at
http://www.dmoz.org/Computers/Programming/Languages/Fortran/Tutorials/Fortran_90_and_95/
) will cover DO loops. Your DO loop below is empty. Do some reading so
you can ask more intelligent questions.

> Here the program is
>
> PROGRAM fattoriale
> IMPLICIT NONE
> INTEGER :: n, nfatt, i
> WRITE(*,*) 'Inserisci un numero'
> READ(*,*) n
> nfatt=i
> DO i = 1,n
> END DO
> WRITE(*,*) nfatt
> STOP
> END PROGRAM fattoriale

From: Sandrus on 25 Sep 2006 10:05

"David Flower" <DavJFlower(a)AOL.COM> ha scritto nel messaggio
news:1159191015.145722.23230(a)i3g2000cwc.googlegroups.com...
>
> Sandrus wrote:
>> Hi. My teacher gave us a program to do factorial (n!).
>> But it does not work fine... it always give -12 as resoult.
>> what do i have to do?
>> i'm not shure but i could have misread 1 in i or viceversa from the
>> blackboard. Will you help me?
>>
>> and please, can anyone explain in a simple way the function of DO?
>>
>> Here the program is
>>
>> PROGRAM fattoriale
>> IMPLICIT NONE
>> INTEGER :: n, nfatt, i
>> WRITE(*,*) 'Inserisci un numero'
>> READ(*,*) n
>> nfatt=i
> (Should read nfatt = 1)

Ok, i'll correct this mistake

>> DO i = 1,n
> (Something missing here, left as an exercise to the student!)

And what's missing, please?
I'm getting mad of that... and i have some difficulties to talk in english
(as i'm italian), so @beilavsky, sorry if i dont find many information about
DO in italian....

>> END DO
>> WRITE(*,*) nfatt
>> STOP
>> END PROGRAM fattoriale
>
> Dave Flower
>


From: e p chandler on 25 Sep 2006 11:12

Sandrus wrote:
> "David Flower" <DavJFlower(a)AOL.COM> ha scritto nel messaggio
> news:1159191015.145722.23230(a)i3g2000cwc.googlegroups.com...
> >
> > Sandrus wrote:
> >> Hi. My teacher gave us a program to do factorial (n!).
> >> But it does not work fine... it always give -12 as resoult.
> >> what do i have to do?
> >> i'm not shure but i could have misread 1 in i or viceversa from the
> >> blackboard. Will you help me?
> >>
> >> and please, can anyone explain in a simple way the function of DO?
> >>
> >> Here the program is
> >>
> >> PROGRAM fattoriale
> >> IMPLICIT NONE
> >> INTEGER :: n, nfatt, i
> >> WRITE(*,*) 'Inserisci un numero'
> >> READ(*,*) n
> >> nfatt=i
> > (Should read nfatt = 1)
>
> Ok, i'll correct this mistake
>
> >> DO i = 1,n
> > (Something missing here, left as an exercise to the student!)
>
> And what's missing, please?
> I'm getting mad of that... and i have some difficulties to talk in english
> (as i'm italian), so @beilavsky, sorry if i dont find many information about
> DO in italian....

Insert this statement here - for teaching purposes

WRITE(*,*) i

>
> >> END DO
> >> WRITE(*,*) nfatt
> >> STOP
> >> END PROGRAM fattoriale
> >

This will show you what happens to the variable i each time you go
through the loop.

You have already been given a hint to set nfatt to 1 before you enter
the loop. It should not be too hard to figure out what you have to do
*inside* the loop to the variable nfatt so that the final value of
nfatt will be what you want.

-- Elliot
-- e-mail: epc8 at juno dot com

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