Sharp PC-1500A Instruction Manual page 58

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10 DATA 1,2,3
20
READ A, B, C
30 READ D
To correct this >ituation, we may add a data item to line 10:
10 DATA1,2,3,65
..2!:..
i.ve may use a separate DATA statement, anywhere within the prooram:
10 DATA 1, 2, 3
20 READ A, B. C
30 READ D
40 DATA 65
This illustrates that SHARP views all of the DATA statements within a program as
o
single list
of data items. As the computer encounters each variable name within a READ statement, it
assigns the next data item from the list to that variable. If SHARP cannot fulfill a request for a
data item it stops the program and signals an error. Extra items which are unused when the
program finishes in a normal manner, are ignored.
If
the type (character or numeric) of the next item does not match
the type
of
the
varinble
to be filled, an error will occur. Good programmers group data items into separ<>te DATA state·
mcnts, each of which corresponds to its READ statement within the program. This is illustrated
in the following program which reads three data items four times:
10
DATA 1, "A'', 1
20 DATA 2,
"O", 3
30 DATA
5,
.. c· " , a
40 DATA 13, "D", 21
50 FOR I = 1 TO 3
60 READ A, AS, Z
70
T=T+A*Z
80 NEXT I
Lines 10 through 40 could have been written as:
10 DATA 1. "A", 1, 2, "8", 3, 5, "C", 8. 13, ''0"', 21
or even as:
10 DATA 1
20 DATA "A"
30
DATA 1
40 DATA 2
Cetcl
Both of the$e alternate forms obscure the
fact
that three data items are read, each time, by the
READ statement. The alternate forms also make it more difficult to verify the types of the data
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