HP 40G manual Loop commands

REPLACE	Replaces portion of graphic in graphicname1 with
	graphicname2, starting 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

DO…UNTIL

…END

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 is a loop structure that executes the loop- clause repeatedly 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
	UNTIL A == 12
	END
WHILE…	While ... Repeat ... End is a loop structure that repeatedly
REPEAT…	evaluates test-clauseand executes loop-clausesequence if the
END	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

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