How use gfortran from gcc47 port?

[Murray Eisenberg]

I've installed the port gcc47 @4.7.3. Now how do I use it to compile a FORTRAN program. E.g., suppose I have file "sum.f":

==================================
      program sum

      implicit none
      real a,b,s
c
      print *, ' Type two numbers:'
      read *, a, b
      s = a + b
      print *, s
      stop
      end

================================

What exactly do I type at the Terminal command line to compile that, and what kind of name do I give for the output file (sum.bin or sum.cmd or what?)

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Murray Eisenberg                     murrayeisenberg at gmail.com
80 Fearing Street                      phone 413 549-1020 (H)
Amherst, MA 01002-1912