ZEROGROB

Creates a blank graphic with given width and height,

 

and stores it in graphicname.

 

ZEROGROB graphicname;width;height:

Loop commands

Loop hp allow a program to execute a routine repeatedly. The HP 39gs 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-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 A:

DO

 

A + 1

A

 

DISP 3;A:

 

UNTIL A == 12 END:

WHILE…

While ... Repeat ... End is a loop command that

REPEAT…

repeatedly evaluates test-clauseand executes loop-clause

END

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 A:

 

 

WHILE A < 12 REPEAT

 

A+1 A

 

 

DISP 3;A:

 

END:

 

FOR…TO…STEP

FOR name=start-expression TO end-expression

...END

[STEP increment];

 

loop-clause

END

 

FOR A=1 TO 12 STEP 1;

DISP 3;A:

END:

Programming

18-23