! 2.6.f90
! 20140211 1.1
! $Id: 2.6.f90 1.5 2025/07/13 10:41:57 s Exp $
!
! r  : a rate
! i  : an index strem
! x  : a cash flow stream
! pv : a preset value

module subprog
    implicit none
contains
    function pv(x, r, ii) result(v)
        real(8), intent(in) :: x(:)
        real(8), intent(in) :: r
        integer, intent(in) :: ii(:)
        real(8) :: v
        v = sum(x(:) / (1.0d0 + r / 12d0) ** ii(:))
    end function
end module subprog

program ex2_6
    use subprog
implicit none
integer, parameter :: n1 = 6, n2 = 6, n3 = 12, n4 = 12
real(8)   pv1,    pv2,    pv3,    pv4, r
integer i1(n1), i2(n2), i3(n3), i4(n4)
real(8) x1(n1), x2(n2), x3(n3), x4(n4)
integer k

! input
r = 0.12d0
i1(:) = (/(k, k=0, n1-1)/)
i2(:) = (/(k, k=0, n2-1)/)
i3(:) = (/(k, k=0, n3-1)/)
i4(:) = (/(k, k=0, n4-1)/)
x1(:) = -1000.0d0
x2(:) =  -900.0d0
x2(1) = x2(1) - 1000.0d0
x3(:) = -1000.0d0
x4(:) =  -900.0d0
x4(1) = x4(1) - 1000.0d0

! calculation
pv1 = pv(x1(:), r, i1(:))
pv2 = pv(x2(:), r, i2(:))
pv3 = pv(x3(:), r, i3(:))
pv4 = pv(x4(:), r, i4(:))

! output
write(*,*) '2.6.f90'
write(*,*) 'input'
write(*,'(a5,f7.2)') 'r=',  r
write(*,'(a5,12i7)') 'i1=', i1(:)
write(*,'(a5,12i7)') 'i2=', i2(:)
write(*,'(a5,12i7)') 'i3=', i3(:)
write(*,'(a5,12i7)') 'i4=', i4(:)
write(*,'(a5,12i7)') 'x1=', int(x1(:))
write(*,'(a5,12i7)') 'x2=', int(x2(:))
write(*,'(a5,12i7)') 'x3=', int(x3(:))
write(*,'(a5,12i7)') 'x4=', int(x4(:))
write(*,*) 'output'
write(*,'(a5,i7)') 'pv1=', int(pv1)
write(*,'(a5,i7)') 'pv2=', int(pv2)
write(*,'(a5,i7)') 'pv3=', int(pv3)
write(*,'(a5,i7)') 'pv4=', int(pv4)
end program
! end