Global Variables in FORTRAN

[shalinibasu82]

Hello,

I am new to FORTRAN and just getting hang of it. I have a global variable say counter which I need to pass to a subroutine and do some processing.

FIRST.f90
integer counter
common /coun/counter
counter = 1000
call second

In SECOND.f90
subroutine second
common /coun/counter

print *,'counter is ',counter

counter = counter - 1

print *,'counter is', counter
end


Current I am getting a garbage value. Please let me know if I am missing something. Thanks.

Shalini

 

[ArkM]

You must declare identical types for all common block elements in every item. By default you have real counter var in the second subroutine but it is declared (and initialized) as an integer in the main program. Integer value 1000 is a garbage data when treated as a real (floating point) in the subroutine.