Prog. Langs (Fortran) 3

! x^3 - 8 = 0 (1 --- 4)
function f(x) result(y)

    real(16), intent(in)::x
    real(16)::y

    y = x*x*x - 8

end function

function df(x) result(y)

    real(16), intent(in)::x
    real(16)::y

    y = 3*x*x

end function

program hello

    real(16)::f
    real(16)::df
    real(16)::a, b, c, d, e
    a = 1
    b = 4

    do while ((b - a) > 0.000000000001)
        c = f(a)
        d = f(b)
        e = df(b)
        a = -f(a)*(b-a)/(f(b)-f(a))+a
        b = -f(b)/df(b) + b
    end do

    Print *, a
    Print *, b

end program Hello

! SECONDS EXAMPLE
program hello

    real(8)::x
    real(8)::y

    x = .75
    y = dsqrt(x)

    do while (dabs(y-x) > 0.00000000000001)
        x = y
        y = dsqrt(x)
    end do

    Print *, y

end program Hello