日本畜産統計戦略会議（JCSAS）

全角数字「１２３」などを半角数字「123」などに変換するプログラム部品（Fortran90）です。
これを応用すれば、ある部分を変更するだけで他の文字などへも変更できます。
どうぞご利用ください。

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!tm -------------------------------------------------------
  subroutine chg_fd2hd(ifile, ofile)
!tm 全角数字 -> 半角数字
    integer (8), parameter :: in_unit = 9917
    integer (8), parameter :: out_unit = 9918
    character (len=2) :: moji
    character (*) :: ifile, ofile
    open (in_unit, file=ifile, access='stream', form='formatted', status='unknown')
    open (out_unit, file=ofile, access='stream', form='formatted', status='unknown')
    do
      read (in_unit, '(a)', advance='no', eor=100, end=110) moji(1:1) ! read the first byte
      if (ichar(moji(1:1))>127) then ! assume two-byte character if 1st byte is > 127
        read (in_unit, '(a)', advance='no') moji(2:2) ! read the 2nd byte
        if (moji(1:1)==char(130) .and. moji(2:2)>=char(79) .and. moji(2:2)<=char(88)) then ! if moji is full-width digit
          write (out_unit, '(a)', advance='no') char(48+ichar(moji(2:2))-79) ! convert to half-width digiti
        else
          write (out_unit, '(a)', advance='no') moji ! two-byte char output as is
        end if
      else
        write (out_unit, '(a)', advance='no') moji(1:1) ! single byte char output as is
      end if
      cycle
      100 write (out_unit, '()') ! new record
    end do
    110 continue
    close (in_unit)
    close (out_unit)
  end subroutine chg_fd2hd

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