program porte_vecteur

  implicit none

  !integer :: N, k
  !real :: L, gama, pi

  real :: L,C0,C1,xd,xf
  !real :: x
  integer :: N, k
  real :: H, C_init
  real, dimension(100) :: x_reg, C

  call recup_donnees(N,L,C0,C1,xd,xf)

  call mesh(N,L,x_reg)

  call init_c(N,L,C0,C1,xd,xf,x_reg,C)

  do k=1,N
    print*,"Au point numero k= ",k," x= ",x_reg(k),", C= ",C(k)
  end do

end program porte_vecteur


!------------
function H(x)

  implicit none
  real, intent(in) :: x
  real :: H

  if (x<0) then
          H = 0.
  else
          H = 1.
  end if

end function H


!-------------------------------
function C_init(x,L,C0,C1,xd,xf)

  implicit none
  real, intent(in) :: x,L,C0,C1,xd,xf
  real :: H
  real :: C_init

  C_init = C0 + (C1-C0)*(H(x-xd)-H(x-xf))

end function C_init


!--------------------------------------
subroutine recup_donnees(N,L,C0,C1,xd,xf)

        implicit none
        integer, intent(out) :: N
        real, intent(out) :: L,C0,C1,xd,xf

        print*, "Donner la valeur de N (N<=100):"
        read*, N
        print*, "Donner la valeur de L:"
        read*, L
        print*, "Donner la valeur de C0:"
        read*, C0
        print*, "Donner la valeur de C1:"
        read*, C1
        print*, "Donner la valeur de xd:"
        read*, xd
        print*, "Donner la valeur de xf:"
        read*, xf

end subroutine recup_donnees



!-------------------------
subroutine mesh(N,L,x_reg)

        implicit none
        ! Variables en arguments
        integer, intent(in) :: N
        real, intent(in) :: L
        real, dimension(100), intent(out) :: x_reg
        ! Variables locales
        integer :: k

        do k=1,N
          x_reg(k) = L / real(N-1) * real(k-1)
        end do

end subroutine mesh

!-----------------------------------------
subroutine init_c(N,L,C0,C1,xd,xf,x_reg,C)

        implicit none
        ! Variables en arguments
        integer, intent(in) :: N
        real, intent(in) :: L,C0,C1,xd,xf
        real, dimension(100), intent(in) :: x_reg
        real, dimension(100), intent(out) :: C
        ! Variables locales
        integer :: k
        real :: C_init

        do k=1,N
           C(k) = C_init(x_reg(k),L,C0,C1,xd,xf)
        end do

end subroutine init_c