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ERROR Statement Programming Example
 
This example uses an ERROR statement in an error-handling
routine, Handler, to trap a user input error.
 
  Tip:  You must supply a text file when you run this example.
        Use a text file you have already created, create a file
        with a text editor, or specify the README.DOC text file.
 
ON ERROR GOTO Handler
OpenFile:
    INPUT "Name of file to update"; FileSpec$
    IF FileSpec$ = "" THEN END
    OPEN FileSpec$ FOR INPUT AS #1
    PRINT "The first five lines of "; FILESPEC$;" are:" : PRINT
    FOR I = 1 TO 5
        LINE INPUT #1, Temp$
        PRINT Temp$
    NEXT
    PRINT : INPUT "Is this the correct file"; R$
    'Define error 200.
    IF LEFT$(R$,1) <> "y" THEN ERROR 200
    END
 
Handler:        'Error-handling routine.
    Number = ERR
    'If program generates run-time error for "file not found,"
    'a special message is printed and the user is prompted to
    'enter a new file specification or end the program.
    IF Number = 53 THEN
        CLOSE #1
        PRINT "File not in this directory"
        PRINT "Enter new file spec ([d:]xxx...xxx) or"
        PRINT "press <RETURN> to end program"
        RESUME OpenFile
    ELSEIF Number = 200 THEN    'User entered "n"
        CLOSE #1
        RESUME OpenFile
    ELSE
        ERROR Number       'Error other than 53 or 200.
        ON ERROR GOTO 0    'Print message, disable error
    END IF                 'handling, and stop program.