一个关于无类型指针的问题

weixing1531

楼主的设想还是可以实现的
只是class(*)多态指针p的断开引用必须在select type内部才行     
  但Fortran2018标准已经放松该限制  
  摘自电子书《Modern Fortran Explained  Incorporating Fortran 2018》
  下载网址：http://www.doc88.com/p-0601727992809.html

[Fortran] 纯文本查看 复制代码

program main
    implicit none
    integer,target::a=3
    real,target::b=8.15
    class(*),pointer::p
    
    ALLOCATE(p,source=a) !f2018标准支持 p=a
    call write_p(p)
    p=>b
    call write_p(p)
    ALLOCATE(p,source=b) !f2018标准支持 p=b
    call write_p(p)
    p=>a
    call write_p(p)
contains
    subroutine write_p(p)
        class(*),pointer,intent(in)::p

        select type(p)
        type is(integer)
            write(*,"(I3)")p
        type is(real)
            write(*,"(F8.2)")p
        end select
    end subroutine write_p
end program