Fortran Simple program in Fortran, I get an error

[fluidistic]

It's not an assignment. Rather I'm trying to learn back some fortran.
I've found a website with some simple problems to do, that's where I got this one. See the first problem of this page : http://www.chem.ox.ac.uk/fortran/.

Here's my program :
Program vasy
implicit none

Integer :: C
Real :: F

C=0
F=0
do while (C<=100)
F=(9./5.)*C+32
C+1
write(*,*)C,F

end do


end program vasy

Here's the error I'm getting : "
C+1
1
Error: Unclassifiable statement at (1)
"
I know I didn't have to set F=0, but I tried several things in case the error was there... I can't get rid of the problem. My compiler is goftran and I'm under Ubuntu.

 

[fluidistic]

Nevermine, I just saw my problem. I had to write a=a+1 instead of just a+1.

Now I'm getting a permission denied when executing the program, but I think I'll solve it.
Thanks anyway!