io - How are input lines defined for I/0 statements? -


i want read values file called input.txt. input file looks this:

    1       2       3       4     1       2       3       4     1       2       3       4     1       2       3       4     1       2       3       4     1       2       3       4   ....

in total 36 lines of 1,2,3 , 4s

then use following code read file:

program outputtest     implicit none     double precision, allocatable, dimension(:) :: a,b,c,d     integer :: counter,ii, ierror     ierror=0     counter=1     open(39, action='read', name='input.txt', status='old')         read(39,100, iostat=ierror)     100 format(t8,i1)     if (ierror>0)             print *, 'error when reading'             stop     end if     if (ierror<0)             print*, 'end of file reached'             exit     end if      counter=counter+1     end     if (.not.allocated(a)) allocate(a(counter))     if (.not.allocated(b)) allocate(b(counter))     if (.not.allocated(c)) allocate(c(counter))     if (.not.allocated(d)) allocate(d(counter))     ii=1, counter-1             read(39,110, iostat=ierror) a(ii), b(ii), c(ii), d(ii)             110 format(t8, i4, t16, i4, t24, i4, t32, i4)             if (ierror.neqv.0) exit     end     close(39)     write (*,120)      write (*,120) b     write (*,120) c     write (*,120) d     120 format('result:', 1x,i2)   end program outputtest

the problem a,b,c,d equal zero, i.e. output is:

result: 0 result: 0 result: 0 ....

this means not read either correct lines or make mistake. used in vim option ruler see lines entries in , used lines t. created file input.txt using tabs. mistake?

a 2 things:

  1. you don't rewind in file. @ first read through whole file number of lines, without rewind, start reading @ end -- means nothing gets read arrays.
  2. read explicit formats dangerous. have input file matches format precisely. in case, i'd @high-performance-mark suggested , use fmt=*. input file should read automatically.

that's can gleam quick browse. see if helps.


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