      subroutine datjack(n,x,xj) ! bernd berg, dec 15 2000.
c calculation of  n  jackknife bins  xj(n)  for  n  data in  x(n).        
      include '../../libs/fortran/implicit.sta'
      include '../../libs/fortran/constants.par'
      dimension x(n),xj(n)
      xsum=zero
      do i=1,n
        xsum=xsum+x(i)
      enddo
      factor=one/(n-1)
      do i=1,n
        xj(i)=factor*(xsum-x(i))
      enddo
      return
      end
