＜BACKSPACE Example Program＞

Program backspace_example
  Character(80) :: line
  Open (17,File='INPUT.DAT',Status='OLD',Position='REWIND')
  Do
    Read (17,'(A)',End=1) line
  End Do
1 Continue
  Backspace 17
  Write (17,'(A)') '999'
  Rewind 17
  Do
    Read (17,'(A)',End=2) line
    Print *,Trim(line)
  End Do
2 Close (17)
End Program

＜File: INPUT.DAT＞

1
2
5

■ Execution Results

 1
 2
 5
 999