HP 40gs Loop commands

hp40g+.book Page 23 Friday, December 9, 2005 1:03 AM

Loop commands

DO…UNTIL …END

WHILE…

REPEAT…

END

FOR…TO…STEP

...END

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 is a loop command that executes the loop-clauserepeatedly until test-clausereturns 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 is a loop command that repeatedly evaluates test-clauseand executes loop-clausesequence 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 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:

Programming 21-23