HP 48g Graphing Calculator - Manual (Page 420)

29
The increment value can be positive or negative. If the increment is
positive, the loop is executed again if counter is less than or equal to
finish. If the increment is negative, the loop is executed if counter
is greater than or equal to finish. Otherwise, counter is purged and
execution resumes following STEP.
DO...UNTIL...END
Enter this structure into a program by pressing fPRGi B R C H
&) DO . Its syntax is:
■ i: ... D O loop-clause U N T IL test-clause E N D ... s -
DO...UNTIL...END executes the loop-clause sequence repeatedly until
test-clause returns a true (nonzero) result. Because the test-clause is
executed after the loop-clause, the loop-clause is always executed at
least once.
DO starts execution of the loop-clause. UNTIL marks the end of
the loop-clause. The test-clause leaves a test result on the stack.
END removes the test result from the stack. If its value is zero,
the loop-clause is executed again—otherwise, execution resumes
following END. If the argument of END is an algebraic or a name, it’s
automatically evaluated to a number.
WHILE...REPEAT...END
Enter this structure into a program by pressing f PRGl i3 R C
Qi-'
. t . Its syntax is:
W H IL E test-clause R E P E A T loop-clause
WHILE...REPEAT...END repeatedly evaluates test-clause and
executes the 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.
WHILE starts execution of the test-clause, which returns a test result
to the stack. REPEAT takes the value from, the stack. If the value
is nonzero, execution continues with the loop-clause—otherwise,
execution resumes following END. If the argument of REPEA.T is an
algebraic or a name, it’s automatically evaluated to a number.
29-14 Programming the HP 48