program leggo2din
implicit none

! lettura fino a end of file con vettore dinamico
! open -- conta e poi alloca e legge
!

integer ::n,i,iend
real, allocatable,dimension(:) :: x
real:: xm,xx
character (len=40) :: nome

1 Write(6,*)'Nome File?'
read(5,'(a)')nome
open (unit=50,status='old',file=nome,err=1)

do i=1,1000000
   read(50,*,iostat=iend)xx
   if(iend /= 0)exit
enddo
if(iend > 0)then
   write(6,*)'Errore di lettura :',iend
   stop
endif

n=i-1
write(6,*) 'Lette ',n,' righe'

rewind(50)
allocate(x(n))
do i=1,n
   read(50,*)x(i)
enddo

xm=0
do i=1,n
   xm=xm+x(i)
enddo
xm=xm/n
write(6,*) 'media=',xm

end program leggo2din