2.5 part 4

code を Fortran で書く。

code

! 2.5.f90
! 2025/07/13
!
! r,  a rate
! n,  a nunber of years
! i,  an index stream
! x,  a cash flow stream
! pv, a present value

program ex2_5
    implicit none
    integer, parameter :: n = 20
    integer, dimension(n) :: ii
    real(8), dimension(n) :: x
    real(8) pv, r
    integer k

    ! input
    r = 0.1d0
    ii(:) = (/(k, k = 0, n - 1)/)
    x(:)  = 500.0d3
    pv    = sum(x(:) / (1.0d0 + r) ** ii)

! output
    write(*, *) '2.5.f90'
    write(*, '(a5, i5)')   'n= ',  n
    write(*, '(a5, f5.3)') 'r= ',  r
    write(*, '(a5, 20i3)') 'i= ',  ii(:)
    write(*, '(a5, 20i7)') 'x= ',  int(x(:))
    write(*, '(a5, i10)')  'pv= ', int(pv)
    return
end program ex2_5
! end of file

output

 2.5.f90
  n=    20
  r= 0.100
  i=   0  1  2  3  4  5  6  7  8  9 10 11 12 13 14 15 16 17 18 19
  x=  500000 500000 500000 500000 500000 500000 500000 500000 500000 500000 500000 500000 500000 500000 500000 500000 500000 500000 500000 500000
 pv=    4682460

history

2023-01-14 create.
2025-07-06 revise.
2025-07-13 revise.