Fortran指针再探

旧城等待， 2024-02-17 18:33 46阅读 0赞

到本帖为止，关于Fortran的初中级部分已基本（我能想到的）截稿，这包括了最常用的部分，如果想写一些东西，或者想做点事情的，完全没有问题了。
    祝大家在Fortran的路上Coding Happy !
        ! Fortran  指针再探
    
        program main
    
        use pointer_jiaozl
        implicit none
    
        integer, dimension(10) :: x = (/11, 2, 3, 9, 8, 78, 56, 45, 12, 76/) 
    
    
    
        call structPointer
    
        call locPointer1
    
        call locPointer2
    
        call locPointer3
    
        write(*, '(20i3)') array(x)
    
        end program main
    
    
    
        ! loc -- pointer
        subroutine locPointer1
        implicit none
        integer                     :: i, j =20
        ! 1 将一个指针基变量链接到一个整型指针
        pointer(p, i)
        ! 2 将目标对象地址赋值给整型指针
        p = loc(j)
        i = 40; j = 90;
        print *, loc(j), p, i, j
    
        end subroutine locPointer1
    
        subroutine locPointer2
        implicit none
        ! 通过pointer语句，将指针基数组b与目标数组a建立联系，
        ! 即指针p中存放的数组a的起始地址就是b的起始地址
        real                        :: a(10), b(5)
        pointer(q, b)
    
        q = loc(a)
        a(2) = 125.0
        print *, b(2)
    
        end subroutine locPointer2
    
        subroutine locPointer3
        implicit none
        ! 通过指针运算和指针基变量b的赋值操作，生成数组a的5个元素值。
        ! 整型指针p增加8（为一个整型变量的字节长度），相当于把数组的下标加1
        integer     :: i
        integer(kind = 8)     :: a(5), b
        pointer(p, b)
    
        p = loc(a)
    
        do i = 1, 5
            b = i * 10
            p = p+8
        end do
    
        print *, a
    
        end subroutine locPointer3
    
         ! 1 结构体指针
        subroutine structPointer
        implicit none
        type person
            character(20)   :: pname
            integer         :: page
        end type person
    
        type(person), target        :: xiaoming
        type(person), pointer       :: ppointer
    
        ppointer=>xiaoming
        ppointer%pname = 'xiaoming'
        ppointer%page = 23
        print *, xiaoming
        print *, ppointer
    
        end subroutine structPointer
    
            module pointer_jiaozl
        contains
        ! 指针数组作为函数值返回
        function array(a)
            integer, dimension(:), pointer      :: array
            integer, dimension(:)               :: a
            integer                             :: i, j, t
            allocate(array(size(a)))
            array = a
            do i = 1, size(a)-1
                do j =i+1,size(a)
                    if(array(i)>array(j)) then
                        t = array(j)
                        array(j) = array(i)
                        array(i) = t
                    end if
                end do
            end do
    
        end function array
    
        end module pointer_jiaozl