Fortran - Odd behaviour (beginner)

Author

Odd behaviour (beginner)

Oodini

2004-03-27, 12:17 am

Hello,

Reading my Fortran book, I typed this little program:

-------------------------------------------------------
! Test the number of opening and closing parenthesis in a line

PARAMETER (LINESIZE = 80)
CHARACTER (LINESIZE)::LIGNE

PRINT *, "Enter expression on 1 line:"
READ *, LIGNE
LEVEL=0
DO I=1, LINESIZE
! IF (LIGNE(I:I)/=' ') THEN
! PRINT *,"Caractere",I,":", &
! LIGNE(I:I)," LEVEL=",LEVEL
! ENDIF
SELECT CASE (LIGNE(I:I))
CASE ('('); LEVEL=LEVEL+1
CASE (')')
LEVEL=LEVEL-1
IF (LEVEL<0) THEN
PRINT *, &
"Bad closing parenthesis",I
STOP
ENDIF
END SELECT
END DO
IF (LEVEL>0) THEN
PRINT *,"Missing closing parenthesis."
ELSE
PRINT *,"Expression is correct."
ENDIF
END PROGRAM
-------------------------------------------------------

The problem is that whatever the expression I type, the program takes as
the first character of the line the first character after the last '*'.

Ie, in the expression: (a*(x2+y2)+b*y*zdx*z)
The program reacts as if I typed: z)

If I type only a*(x2+y2), the program react as if I typed only (x2+y2)

You can constat that if you remove the commented code.

Thanks for help.

James Giles

2004-03-27, 12:17 am

Oodini wrote:
....
> PARAMETER (LINESIZE = 80)
> CHARACTER (LINESIZE)::LIGNE
>
> PRINT *, "Enter expression on 1 line:"
> READ *, LIGNE
....
> The problem is that whatever the expression I type, the program takes as
> the first character of the line the first character after the last '*'.
>
> Ie, in the expression: (a*(x2+y2)+b*y*zdx*z)
> The program reacts as if I typed: z)
>
> If I type only a*(x2+y2), the program react as if I typed only (x2+y2)
>

Reading undelimited character data with a list-directed read is
not a particularly good idea if the data contains (or might contain)
spaces, commas, slashes, or asterisks. You probably should use
an explicit format:

READ(*,'(A)') LIGNE

On standard conforming implementations, this will read the record
(or, up to 80 characters of it, in this case) without any other processing
of its content.

--
J. Giles

Oodini

2004-03-27, 12:17 am

> Reading undelimited character data with a list-directed read is
> not a particularly good idea if the data contains (or might contain)
> spaces, commas, slashes, or asterisks. You probably should use
> an explicit format:
>
> READ(*,'(A)') LIGNE
>
> On standard conforming implementations, this will read the record
> (or, up to 80 characters of it, in this case) without any other processing
> of its content.

OK. It does work now !
The info you gave me is at thje end of the book...

Thanks for your help !

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