! -------------------------------
! Example program
! 
! A simple user-defined data type
! with operator overloading
! -------------------------------
module structures

  type rational
     integer  :: numer,denom
  end type rational

 interface operator (+)
    module procedure addrats
 end interface

 contains
   function addrats(rat1,rat2) result (sumrat)
     type(rational), intent(in):: rat1,rat2
     type(rational):: sumrat
     integer:: a,b,c,d
     a = rat1%numer
     b = rat1%denom
     c = rat2%numer
     d = rat2%denom
     sumrat%numer = a*d+c*b
     sumrat%denom = b*d 
   end function addrats

end module structures

program test
  use structures
  implicit none
  type(rational):: rat1,rat2
  real(kind(1.d0)):: decimal 
  rat1%numer = 2
  rat1%denom = 3
  rat2%numer = 1
  rat2%denom = 5

  write(*,'(i0,"/",i0)') rat1,rat2,rat1+rat2

end program test