fortran中open中可以使用已定义的字符串变量，关键是不能省略file=

program main 
      implicit none
      integer,parameter :: number=160
      integer,parameter :: lanzhou=138
      integer,parameter :: byear=1951!the beginning
      integer,parameter :: cyear=2017! the current
      integer,parameter :: time=cyear - byear+1
      integer,dimension(number, time) :: it
      integer :: i,j,k
      character(len=10),dimension(12) :: month
      data month /"Jan", "Feb", "Mar", "Apr", "May", "Jun", &
                  "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"/
      do k=1,12,1
        open(11,file="./temperature/"//trim(month(k))//".txt")
        read(11,*) ((it(i,j), i=1,number),j=1,time)
        open(12,file="./temperature/"//trim(month(k))//"lanzhou.txt")
        write(12,"(2i5)") (i,it(lanzhou,i),i=1,time)
        close(11)
        close(12)
      end do
end program main

write的fmt应该也是如此逻辑。