!-----------------!
 program craverage
!-----------------!
 implicit none

 integer :: i,r,ll,bins
 real(8) :: c

 real(8), allocatable :: cr(:,:)

 open (10,file='read.in',status='old')
 read(10,*)ll
 close(10)

 allocate(cr(2,0:ll/2))

 bins=0
 cr=0.d0
 open (10,file='cor.dat',status='old')
 do 
   do r=0,ll/2
      read(10,*,end=10)i,c
      cr(1,r)=cr(1,r)+c
      cr(2,r)=cr(2,r)+c**2
   enddo
   bins=bins+1
 end do
 10 close(10)
 write(*,*)bins
 cr=cr/bins
 cr(2,:)=sqrt((cr(2,:)-cr(1,:)**2)/(bins-1))
 
 open (10,file='c.dat')
 do r=0,ll/2
    write(10,'(i6,2f15.8)')r,cr(:,r)
 enddo
 close(10)

 deallocate(cr)

 end program craverage
!---------------------!