How to store a set of functions into a Fortran array

Question

As we know that function name can be treated as parameters to pass in/out by other subroutines. I wonder if we have any tricks to save a list of functions into an array, whi

Answer 1

Firstly you should create a type that contain only a procedure pointer that doesn't pass any argument. and then create an array of that type.

Example:

program test_func_array
   implicit none

   type pp
    procedure(func) ,pointer ,nopass :: f =>null()
   end type pp

   interface
      function func(x)
         real :: func
         real, intent (in) :: x
      end function func
   end interface

   type(pp) :: func_array(4)

   func_array(1)%f => exp
   func_array(2)%f => tan
   func_array(3)%f => cos
   func_array(4)%f => sin

   print*,func_array(1)%f(1.)
   print*,func_array(2)%f(1.)
   print*,func_array(3)%f(0.)
   print*,func_array(4)%f(0.)  

end program test_func_array