Loop commands – HP 39g+ User Manual
Page 228
15-22
Programming
REPLACE
Replaces portion of graphic in graphicname1 with
graphicname2
,
s
tarting at position
.
REPLACE
also works
for lists and matrices.
REPLACE
graphicname1
;
(position)
;
graphicname2:
SUB
Extracts a portion of the named graphic (or list or matrix), and
stores it in a new variable, name. The portion is specified by
position and positions.
SUB
name
;
graphicname
;
(position)
;
(positions):
ZEROGROB
Creates a blank graphic with given width and height, and
stores it in graphicname.
ZEROGROB
graphicname
;
width
;
height:
Loop commands
Loop structures allow a program to execute a routine
repeatedly. The HP 39G/40G 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 structure 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
&
A:
DO A + 1
&
A
UNTIL A = = 12
END
WHILE…
REPEAT…
END
While
...
Repeat
...
End
is a loop structure 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
&
A:
WHILE A < 12
REPEAT A+1
&
A
END