HP 40gs - Manual (Page 371)

Programming 21-23
Loop commands
Loop hp allow a program to execute a routine repeatedly.
The HP 40gs has three loop structures. The example
programs below illustrate each of these structures
incrementing the variable A from 1 to 12.
DO…UNTIL …END Do ... Until ... End is a loop command that executes the
loop-clause repeatedly until test-clause returns a true
(nonzero) result. Because the test is executed after the
loop-clause, the loop-clause is always executed at least
once. Its syntax is:
DO loop-clause UNTIL test-clause END
1 X A:
DO
A + 1 X A:
DISP 3;A:
UNTIL A == 12 END:
WHILE…
REPEAT…
END While ... Repeat ... End is a loop command that
repeatedly evaluates test-clause and executes loop-clause
sequence if the test is true. Because the test-clause is
executed before the loop-clause, the loop-clause is not
executed if the test is initially false. Its syntax is:
WHILE test-clause REPEAT loop-clause END
1
X A:
WHILE A < 12 REPEAT
A+1 X A:
DISP 3;A:
END:
FOR…TO…STEP
...END FOR name=start-expression TO end-expression
[STEP increment]; loop-clause END
FOR A=1 TO 12 STEP 1;
DISP 3;A:
END:
Note that the STEP parameter is optional. If it is omitted,
a step value of 1 is assumed.
BREAK Terminates loop.
BREAK:
hp40g+.book Page 23 Friday, December 9, 2005 1:03 AM