FORTRAN Open Arbitrary number of files in Do Loop

• Fortran
I have a quick question that I've always wondered exactly how to do but never needed to. Well of course now I do. I have a DO loop that loops an arbitrary number of times. I would like to open a file each time it comes around, using the DO loop iterator as part of the filename. Ideally, it would look something like....
Code:
n = 5
DO i=1,n
OPEN(11,file='input000',i,'.fmt',form='formatted')
blah blah blah
CLOSE(11)
END DO
So, if anyone knows how to parse the variable into that text string, I would appreciate it. Thanks,

Related Programming and Computer Science News on Phys.org
I do not know what version of Fortran you run, but this example should be close to what you can do.

Code:
      IMPLICIT INTEGER(I-N), REAL*8(A-H,O-Z)
N=5
CHARACTER *10 FN
DO 5 I=1,N
WRITE(FN,10)I
WRITE(6,*)FN
OPEN(1,FILE=FN)
CLOSE(1)
5 CONTINUE
10 FORMAT(5HINPUT,I3.3)
STOP
END
The screen output looks like this, and the corresponding files have been opened (and closed):
Code:
INPUT001
INPUT002
INPUT003
INPUT004
INPUT005

BTW, I'm using FORTRAN90. I get that and it'll get me 90% there. How can I then add a '.fmt' as a file extension? I imagine the period needs some special character designation?

Thanks,

You only have to add the suffix at the end of the format statement, and don't forget to inccrease the length of FN to 12, as follows:

Code:
      IMPLICIT INTEGER(I-N), REAL*8(A-H,O-Z)
N=5
CHARACTER *12 FN
DO 5 I=1,N
WRITE(FN,10)I
WRITE(6,*)FN
OPEN(1,FILE=FN)
CLOSE(1)
5 CONTINUE
10 FORMAT('INPUT',I3.3,'.FMT')
STOP
END
I believe the translation to F90 should be trivial.

Beautiful; working. Thanks a bunch!

Glad that everything works out!

Hi everyone

I have got similar problem..

How can i write to an existing file without deleting previous data.

so basically i want to add new info every time i run the program.

Thanks

ENDFILE
OPEN(1, FILE='mydata.dat', ACCESS='APPEND')