我不喜欢fortran，
奇怪的词法规则（竟然不用空格分开token），
io操作竟然是语言的一部分（这种非本质的东西像C那样用库来扩展多好）
。。。
program link
implicit none
type node
character(20) name
integer id
integer score
type(node),pointer ::next
end type
integer,parameter::num=3
type(node),pointer ::students
call init_all(students,num)
call show_all(students)
print*,"now,we add a student"
call add_node(students)
call show_all(students)
print*,"now,we delete the student"
call del_node(students)
call show_all(students)
contains
subroutine add_node(pos)
type(node),pointer ::pos,tmp
allocate(tmp)
tmp%name="abc"
tmp%id=1
tmp%score=100
print*,"please input name,id,end score of one students"
read*,tmp%name,tmp%id,tmp%score
if(associated(pos%next)) then
tmp%next=>pos%next
pos%next=>tmp
else
nullify(tmp%next)
pos%next=>tmp
end if
end subroutine
subroutine del_node(pos)
type(node),pointer ::pos,next
next=>pos%next
if(associated(next%next)) then
pos%next=>next%next
deallocate(next)
else
nullify(pos%next)
deallocate(next)
end if
end subroutine
subroutine show_all(pos)
type(node),pointer ::pos,tmp
integer ::cnt
cnt=1
print*,"all students are:"
tmp=>pos
do while(associated(tmp))
print*,cnt,"th ",tmp%name,tmp%id,tmp%score
tmp=>tmp%next
cnt=cnt+1
end do
end subroutine
subroutine init_all(pos,num)
type(node),pointer ::pos,tmp,walk
integer num
integer i
allocate(tmp)
nullify(tmp%next)
call add_node(tmp)
pos=>tmp%next
deallocate(tmp)
walk=>pos
do i=1,num-1
call add_node(walk)
walk=>walk%next
end do
end subroutine
end program link