coutning characters in a string

[csiegs]

I'm using Fortran 77 - I'm trying to count the number of characters in a string that the user enters. The user enters a a path for a file to be stored to, and then I need to append some numbers to the end of it.

Example:
user enters: c:/march18/file
then the following would be created:
c:/march18/file1000.dat
c:/march18/file1001.dat
c:/march18/file1002.dat
and so on..

The problem is that the number of characters in the pathname changes all the time. I can't use concatentate because then I get trailing spaces after 'file' depending on the length that I declare. I dont want to go in and change the code every time I enter a new path. Annoying!

Please help!
Thanks.

 

[vecjjk]

I'm not sure if it exists within Fortran 77, but in Vax Fortran, there is a function call INDEX where you can find a certain character. If there are no imbedded blanks within the string, you could use INDEX to find the position of the first blank, then subtract 1 to have the end of the string. If INDEX won't work, you could search the string manually from the end and stop when you hit a non-blank character. Something like this. CUR_POS would end up being the last character of the string. In this example, CUR_POS would be zero if the string was blank. Not sure if this will work with Fortran 77, but I think you will get the idea.

CHARACTER*10 STR_VAR
INTEGER CUR_POS
LOGICAL DONE

CUR_POS = 0
IF (STR_VAR.NE.' ') THEN ! Make sure string is not blank
CUR_POS = 10
DONE = .FALSE.
DO WHILE(.NOT.DONE)
IF (STR_VAR(CUR_POS:CUR_POS).NE.' ') THEN
DONE = .TRUE.
ELSE
CUR_POS = CUR_POS - 1
END IF
END DO
END IF

 

[xwb]

INDEX is a standard F77 function. It returns the position of a substring within a string.
LEN is also a standard F77 function. It is supposed to return the length of the string but in some implementations, it returns the size of the identifier. For instance,

INTEGER strlen
CHARACTER*8 str
str = 'notice'
strlen = LEN(str)

On some implementations, strlen will be 8, on others it will be 6. For concatenation, you can always use slicing with indices eg

      character*8 one, two
      character*16 three
      integer onelen, twolen
      one = 'leg'
      two = 'end'
      onelen = index(one, ' ')
      twolen = index(two, ' ')
      three = one(1:onelen - 1) // two(1:twolen - 1)

 

[Phil31]

Depending on your fortran implementation and OS, you could sometime find special functions like LNBLNK or LEN_TRIM that returns the length of a string passed as argument wihtout couting the trailling blanks. These functions exists in VisualFortran and UNIX (for LNBLNK).