Trouble with gfortran compiler.

[cyberclown]

I am new to fortran programming, and now I am strugling on how to compile a class using gfortran compiler. If I example try to compile the class class_circle.f90(see under, taken from

http://fortranwiki.org/fortran/show/Object-oriented+programming)

I write: "gfortran -c class_circle.f90" in terminal window. When I do this I get the error given below.
I would really appreciate it if someone knows how to do this and can tell me!


Error message:
-----------------------------------------------------------

cyberclown@jern ~/GEO1331/testing_with_progs $ gfortran -c class_circle.f90
In file class_circle.f90:8

contains
1
Error: Unexpected CONTAINS statement at (1)
In file class_circle.f90:9

procedure :: area => circle_area
1
Error: Unclassifiable statement at (1)
In file class_circle.f90:10

procedure :: print => circle_print
1
Error: Unclassifiable statement at (1)
In file class_circle.f90:14

class(Circle), intent(in) :: this
1
Error: Unclassifiable statement at (1)
In file class_circle.f90:16

area = pi * this%radius**2
1
Error: Unclassifiable statement at (1)
In file class_circle.f90:20

class(Circle), intent(in) :: this
1
Error: Unclassifiable statement at (1)
In file class_circle.f90:22

area = this%area() ! Call the type-bound function
1
Error: Unclassifiable statement at (1)
In file class_circle.f90:23

print *, 'Circle: r = ', this%radius, ' area = ', area
1
Error: Syntax error in PRINT statement at (1)
In file class_circle.f90:19

subroutine circle_print(this)
1
Error: Symbol 'this' at (1) has no IMPLICIT type
In file class_circle.f90:13

function circle_area(this) result(area)
1
Error: Symbol 'this' at (1) has no IMPLICIT type





This is the class:

------------------------------------------------------

module class_Circle
implicit none
private
real :: pi = 3.1415926535897931d0 ! Class-wide private constant

type, public :: Circle
real :: radius
contains
procedure :: area => circle_area
procedure :: print => circle_print
end type Circle
contains
function circle_area(this) result(area)
class(Circle), intent(in) :: this
real :: area
area = pi * this%radius**2
end function circle_area

subroutine circle_print(this)
class(Circle), intent(in) :: this
real :: area
area = this%area() ! Call the type-bound function
print *, 'Circle: r = ', this%radius, ' area = ', area
end subroutine circle_print
end module class_Circle



Main program:
----------------------------------------
program circle_test
use class_Circle
implicit none

type(Circle) :: c ! Declare a variable of type Circle.
c = Circle(1.5) ! Use the implicit constructor, radius = 1.5.
call c%print ! Call the type-bound subroutine
end program circle_test