用Fortran语言编写程序：、编写子程序，该程序可返回数组的中值。已知两个整型数组 a=[1 3 5 7 6 8 2 0], b=[1 3 5 7 6 8 2 0 11 15 20 25 19],请编写主程序，并调用子程序分别计 算两个数组的中值；并分别计算平均值，以及标准差。

以下是用Fortran语言编写的程序，包括主程序和子程序：

program main
    integer :: a(8) = [1, 3, 5, 7, 6, 8, 2, 0]
    integer :: b(13) = [1, 3, 5, 7, 6, 8, 2, 0, 11, 15, 20, 25, 19]
    real :: median_a, median_b, avg_a, avg_b, std_a, std_b

    median_a = median(a, 8)
    median_b = median(b, 13)
    avg_a = average(a, 8)
    avg_b = average(b, 13)
    std_a = stddev(a, 8)
    std_b = stddev(b, 13)

    write(*,*) 'The median of array a is:', median_a
    write(*,*) 'The median of array b is:', median_b
    write(*,*) 'The average of array a is:', avg_a
    write(*,*) 'The average of array b is:', avg_b
    write(*,*) 'The standard deviation of array a is:', std_a
    write(*,*) 'The standard deviation of array b is:', std_b
end program main

real function median(arr, n)
    integer, intent(in) :: arr(n)
    integer :: n
    integer :: i, j, k
    integer :: tmp(n)
    real :: median

    tmp = arr
    do i = 1, n-1
        do j = i+1, n
            if (tmp(j) < tmp(i)) then
                k = tmp(i)
                tmp(i) = tmp(j)
                tmp(j) = k
            end if
        end do
    end do

    if (mod(n, 2) == 0) then
        median = real(tmp(n/2) + tmp(n/2+1)) / 2.0
    else
        median = real(tmp(n/2+1))
    end if

end function median

real function average(arr, n)
    integer, intent(in) :: arr(n)
    integer :: n
    integer :: i
    real :: sum, avg

    sum = 0.0
    do i = 1, n
        sum = sum + real(arr(i))
    end do

    avg = sum / real(n)
end function average

real function stddev(arr, n)
    integer, intent(in) :: arr(n)
    integer :: n
    integer :: i
    real :: sum, avg, std

    avg = average(arr, n)

    sum = 0.0
    do i = 1, n
        sum = sum + (real(arr(i)) - avg)**2
    end do

    std = sqrt(sum / real(n))
end function stddev

编译运行后，程序将输出数组a和b的中值、平均值和标准差。注意，median函数返回的是实数类型，而不是整数类型。