Re: Simple Program, Lots of Issues (F90)

On Thu, 24 Jul 2008 10:55:18 -0700 (PDT), ALevenson posted:

> I just picked up Fortran yesterday at the suggestion of my mentor,
> which for me means I glance through a tutorial and try to get a
> program running that finds primes. I wrote this over the course of
> maybe 15 minutes, debugged it as I was able to over the next 20, and I
> don't think it is even close to compiling. Of course, I can't figure
> out the exact issues with it, so any help would be appreciated.
> 
>       program primes
> 
>       integer :: i, j, k, l, m, n, x
>       real    :: t
>       logical :: notprime, even
> 
> ! Program finds primes up to
> ! upper limit 'x' as defined by user
> 
>       write ( * , * ) 'Please input upper limit, x:'
>       read ( * , * ) x
> 
>       do i = 2, x, 1
> ! Form of FOR loop is
> ! do variable = start val, end val, step size
>          if ( i == 2 ) then
>             write ( * , * ) i
>          end if
>          even = .FALSE.
>          notprime = .FALSE.
>          j = i / 2
>          t = i / 2
>          if ( j == t ) then
>             even = 1
>          else
>             l = SQRT( i )
>             do m = 3, l, 2
>                n = m / 2
>                t = m / 2
>                if ( n == t ) then
>                   notprime = 1
>                end if
>             end do
>          end if
>          if ( notprime == .FALSE. && even == .FALSE. ) then
>             write ( * , * ) i
>          end if
>       end do
> 
>       stop
>       end

Is this to be the sieve of eratosthenos?
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