! 4.11.f90
! 2024-10-20
! $Id: 4.11.f90 1.1 2024/11/02 08:05:31 s Exp $

real(8), dimension(0:100) :: d, f, s
real(8) pv, pv2(0:6), x(0:6), s_percent(0:6), xd(0:6)
integer :: n
integer index(0:6)

! input
n         = 6
x         = [-40, 10,  10,  10,  10,  10,  10]
s_percent = [0.0, 5.0, 5.3, 5.6, 5.8, 6.0, 6.1]
index     = [0,   1,   2,   3,   4,   5,   6]

! calculation
 s(0:n) = s_percent(0:n) / 100.0
 d(0:n) = 1 / (1+ s(0:n)) ** index
xd(0:n) = x(0:n) * d(0:n)
pv      = sum(xd(0:n))

! output
print *, '4.11.f90'
print '(a5,10i8)',   'k',   index(0:n)
print *,'------------------------------------------------------------'
print '(a5,10f8.3)', 's',   s_percent(0:n)
print '(a5,10f8.3)', 'd',   d(0:n)
print '(a5,10f8.3)', 'x',   x(0:n)
print '(a5,10f8.3)', 'xd',  xd(0:n)
print *,'------------------------------------------------------------'
print '(a5,f8.3)',   'pv=', pv

! calculation
f=0.0
d=0.0
do k=1,n
    f(k) = (1 + s(k)) ** k / (1 + s(k - 1)) ** (k - 1) - 1
end do
d(1:n) = 1 / (1 + f(1:n))

pv2(6) = x(6)
pv2(5) = x(5) + d(6) * pv2(6)
pv2(4) = x(4) + d(5) * Pv2(5)
pv2(3) = x(3) + d(4) * Pv2(4)
pv2(2) = x(2) + d(3) * Pv2(3)
pv2(1) = x(1) + d(2) * Pv2(2)
pv2(0) = x(0) + d(1) * Pv2(1)

! output
print *,''
print '(a5,7i8)',   'k',   index(0:n)
print *,'------------------------------------------------------------'
print '(a5,7f8.1)', 's',   s_percent(0:n)
print '(a5,7f8.1)', 'f',   f(0:n)*100
print '(a5,7f8.3)', 'd',   d(0:n)
print '(a5,7f8.3)', 'pv2', pv2(0:n)
print *,'------------------------------------------------------------'
end
! eof