program statvett1
implicit none

integer::i,n,indxmax,indymax
real,allocatable,dimension(:)::x,y
real:: xmedia,ymedia,xmax,ymax

interface

subroutine readdati (x,y,n)
integer:: n
real,allocatable ,dimension(:)::x,y
end subroutine readdati

subroutine readdatiterm (x,y,n)
integer,intent(out):: n
real,allocatable ,dimension(:)::x,y
end subroutine readdatiterm

real function vmed(v,n)
integer:: n
real ,dimension(1)::v
end function vmed

real function vmin(v,n)
integer:: n
real ,dimension(1)::v
end function vmin

real function varianza(v,vmedia,n)
integer,intent(in):: n
real,intent(in) ,dimension(1)::v
real,intent(in) :: vmedia
end function varianza

subroutine vmax(v,n,vmx,indvmax)
integer,intent(in):: n
real,intent(in) ,dimension(1)::v
integer,intent(out):: indvmax
real,intent(out):: vmx
end subroutine vmax

end interface

call readdatiterm (x,y,n)
xmedia=vmed(x,n)
ymedia=vmed(y,n)
call vmax(x,n,xmax,indxmax)
call vmax(y,n,ymax,indymax)

write(6,*)'Numero dati =',n
write(6,*)'xmedia=',xmedia
write(6,*)'ymedia=',ymedia
write(6,*)'xvar=',varianza(x,xmedia,n)
write(6,*)'yvar=',varianza(y,ymedia,n)

write(6,*)'xmax=',xmax," all'indice: ",indxmax
write(6,*)'ymax=',ymax,' all''indice: ',indymax

write(6,*)'xmin=',vmin(x,n)
write(6,*)'ymin=',vmin(y,n)

end program statvett1


subroutine readdatiterm (x,y,n)
implicit none
integer,intent(out):: n
real,allocatable ,dimension(:)::x,y

real:: xx,yy
character (len=30)::nomefile
integer::i,ierr

23 write(6,*)'Nome file'
read(5,'(a)')nomefile
open(unit=50,file=nomefile,status='old',err=23)
i=1
read(50,*,iostat=ierr) xx,yy
do while(ierr == 0)
   i=i+1
   read(50,*,iostat=ierr)  xx,yy
enddo
if (ierr > 0) then
   write(6,*)'Errore numero:', ierr
   stop
endif
n=i-1
rewind(50)
write(6,*) 'primo giro :n =',n

allocate (x(n),y(n))
do i=1,n
   read(50,*) x(i),y(i)
enddo
close(50)
end subroutine readdatiterm


subroutine readdati (x,y,n)
implicit none
integer:: n
real,allocatable ,dimension(:)::x,y

integer::i

read(5,*)n
allocate (x(n),y(n))
do i=1,n
   read(5,*) x(i),y(i)
enddo

end


real function vmed(v,n)
implicit none
integer:: n
real ,dimension(1)::v

integer::i

vmed=0
do i=1,n
   vmed=vmed+v(i)
enddo
vmed=vmed/n
end function vmed

subroutine vmax(v,n,vmx,indvmax)
implicit none
integer,intent(in):: n
real,intent(in) ,dimension(1)::v
integer,intent(out):: indvmax
real,intent(out):: vmx

integer::i

vmx=v(1)
indvmax=1
do i=2,n
   if(vmx < v(i))then
      vmx=v(i)
      indvmax=i
   endif
enddo
end subroutine vmax

real function vmin(v,n)
implicit none
integer:: n
real ,dimension(1)::v

integer::i

vmin=v(1)
do i=1,n
   if(vmin > v(i))vmin=v(i)
enddo
end function vmin

real function varianza(v,vmedia,n)
implicit none
integer,intent(in):: n
real,intent(in) ,dimension(1)::v
real,intent(in) :: vmedia

integer::i

varianza=0
do i=1,n
   varianza=varianza+(v(i)-vmedia)**2
enddo
varianza=varianza/n
end function varianza