Sharp PC-1500 Instruction Manual page 58

All and more about Sharp PC-1500 at http://www.PC-1500.info
10 DATA 1, 2, 3
20 READ
A,
B, C
30 READ D
To correct this situation, we may add a data item to line 10:
10 DATA 1,2, 3, 65
.Q!'..
we may use a separate OATA statement, anywhere within the program :
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
a single list
of data items. As the computer encounters each variable name within a READ statement, it
a.ssigns 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 variable
to be filled, an error will occur. Good programll1lers group data items into separ ate DATA state·
ments, ·each of which corresponds to its READ statement within the program. T his is illustrated
in the following program v1hich reads three data items four times:
10
DATA
1, "A", 1
20
DATA 2, "B", 3
30
DATA 5,
"C", 8
40 DATA 13, "D", 21
so
FOR I = 1 TO 3
60
READ A, A$, Z
70
T = T+A*Z
80
NEXT I
Lines 10 through 40 could have been written as:
10 DATA 1, "A", 1, 2, "B ",, 3, 5, "C", 8, 13, "0", 21
or even as:
10 DATA
20 DATA "A"
30 DATA
40 DATA 2
(etc)
Both of these alternate fo rms obscure the laci ihat 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
S6
Do not sale this PDF !!!