I want to translate MATLAB to fortran

fid = fopen(filename, 'r')

this matlab code to fortran

~iscahr(line)

this matlab code to fortran

sscanf(line, '%f %f %f')

this matlab code to fortran

Answer 1

[Walter Roberson]

For the fopen:

      INTEGER :: fid, fstatus
      fid = 10
      OPEN(UNIT = fid, FILE = filename, READONLY, ACCESS = 'READ',
     +     STATUS = 'OLD', IOSTAT = fstatus)
      IF (fstatus .NE. 0) THEN
        WRITE(*,*) 'Could not open file'
        CALL EXIT(0)
      END IF

for the ~ischar(line) I suspect that the context is to detect end of file. If so then with the above code having set up fstatus as the IOSTAT variable, right after you do the read of the line,

     IF (fstatus < 0) THEN
       EXIT     %exit loop
     END IF

for the sscanf, assuming that the result was assigned to INVAR, at some point in the program,

   REAL*8 :: INVAR(3)
   INTEGER :: I

and the sscanf would be

   READ( line, * ) (INVAR(I), I=1,3)