Rockwell Automation 57C610 Enhanced Basic Language, AutoMax - Manual (Page 53)

6Ć13
(SWITCH_34% is not a boolean variable or a valid
Ărelational expression)
150 IF A% > B% THEN GOTO 700
ELSE GOTO 400
END_IF
(The keyword THEN must be the last item on the first line)
Note that Version 2.0 and later of the AutoMax Programming
Executive supports both the IFĆTHENĆELSE format described above
and the IFĆTHEN format used in Version 1.0 of the AutoMax
Programming Executive (M/N 57C304Ć57C307). Version 1.0,
however, supports only the IFĆTHEN format.
6.5 Program Looping
A loop is the repeated execution of a set of statements. Placing a
loop in a program saves you from duplicating routines and
enlarging a program unnecessarily.
For example, the following two programs will print the numbers from
1 to 10:
Program Without Loop Program With Loop
10 PRINT 1 10 I% =1
20 PRINT 2 20 PRINT I%
30 PRINT 3 30 I% = I% +1
40 PRINT 4 40 IF I% < = 10 THEN 20
50 PRINT 5 50 END
60 PRINT 6
70 PRINT 7
80 PRINT 8
90 PRINT 9
100 PRINT 10
110 END
Both of these programs would result in the following being printed:
1
2
3
4
5
6
7
8
9
10
The program with a loop first initializes a control variable, I%, in line
10. It then executes the body of the loop, line 20. Finally, it
increments the control variable in line 30 and compares it to a final
value in line 40.
Without some sort of terminating condition, a program can run
through a loop indefinitely. The FOR and NEXT statements set up a
loop wherein BASIC tests for a condition automatically each time it
runs through the loop. You decide how many times you want the
loop to run and you set the terminating condition.
The FOR statement has the following format:
FOR variable = expression_1 TO expression_2 {STEP
expression_3}