c
c
c     implicit none: no rules on variable names are assumed by default
c     note: starting in column 7 to be consistent with vintage fortran
      implicit none
c     defining the variables to be integers
      integer a,b,c
      print *,'hello'
      print *,'enter two integers to add together separated by a space'
c     read from the default terminal window
      read *,a,b
      c = a + b
      print *,'values of a, b, c are:', a,b,c
      stop
c     terminate the program
      end
c
c     compile program by typing gfortran -o sum_f sum_ex.f
c     execute program by typing ./sum_f
c