Apple IIe - Page 131

Apple BASIC Reference Guide 131
Example
10 ONERR GOTO 1000
20 INPUT "ENTER A NUMBER"; A
30 PRINT "A="; A
40 END
1000 E =
PEEK (222): REM ERROR CODE
1010
IF E = 255 THEN END: REM Ctrl-C ENTERED
1020 IF E = 254 THE PRINT "INVALID ENTRY": RESUME
1030 IF E = 69 THEN PRINT "NUMBER TOO LARGE/
TOO MANY DIGITS": RESUME
1040 PRINT "ERROR CODE"; E
1050 END
]RUN [Ret]
ENTER A NUMBER ONE [Ret]
INVALID ENTRY
ENTER A NUMBER 7E50 [Ret]
NUMBER
TOO LARGE/TOO MANY DIGITS
ENTER A NUMBER 2. [Ret]
A =5
In line 10, the ON ERR routine is set. When an invalid number was
entered in response to the INPUT statement in line 20, the
program branched to line 1000 where E was assigned the proper
error code. Lines 1010-1030 check the variable E for its value. If E =
255, then a Ctrl-C was entered. If E = 254, an invalid number was
entered. If E = 69, the number entered was too large or had too
many digits. Lines 1020 and 1030 incorporate the RESUME
statement
to branch back to line 20.
• Applesoft
OR
• Integer
OR is a logical math operat~r. This reserved word is generally
used in conjunction with the IF ... THEN statement.