!求数组的中位数（偶数个时取平均值）
    real*8 function median(n,A)
    implicit none
    
    integer :: n
    real*8 :: A(n)
    real*8 :: B(n),temp
    integer :: i,j
    
    !从小到大排序
    B = A
    do i=1,n-1
        do j=i+1,n
            if(B(i)>B(j)) then
                temp = B(i)
                B(i) = B(j)
                B(j) = temp
            end if
        end do
    end do
    
    !按奇偶取中位数
    if(mod(n,2)==1) then
        median = B(n/2+1)
    else
        median = (B(n/2)+B(n/2+1))/2.0
    end if
    
    end function