Loop In A Loop - Sharp MZ-80A Owner's Manual

38
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Loop in a loop
Alice is doing her homework. She
is preparing
a multiplication
table using the
computer,
and a program which
contains
double
FOR
....
NEXT
statements.
10
20
30
40
50
60
FOR X
=
1 TO 9
FOR Y
=
1 TO 9
PRINT X
*
Y
;
NEXTY
PRINT
NEXT X
Loop Y
Loop X
In the FOR
....
NEXT loop for variable X, the FOR
....
NEXT loop for variable Y is included. Variables X and
Y vary from
1 to 9, respectively, and 1 is
substituted for
variable
X
to execute variable
Y
loop. In other words, with
variable
X
remaining at 1, variable
Y
varies 1,2,3
.....
to 9,
and each time, the multiplication
product with variable X
is
displayed
at
line number 30. When varialbe
Y
reaches 9, a line feed is executed
at line number
50, and at line
number
60, variable
X
is then
2.
The FOR
....
NEXT loop can be used double, triple,
etc.,
up
to
15. What must be observed, however, is that loops
are never
crossed and no jump into the loop by means of GOTO
is
allowed.
Thus, loop C is completely included in loop B, while loop B is completely included in loop A. As shown on the
right, one word NEXT can be used for all three loops.