How Enter Works - HP 17bll+ User Manual

How ENTER Works

You know that
E
other. In terms of the stack, how does it do this ? Suppose the stack is
filled with a, b, c, and d. Now enter and add two new numbers:
T
a
Z
b
Y
c
X
d
5
replicates the contents of the X-register into the Y-register. The
E
next number you key in (or recall) writes over (instead of lifting) the copy
of the first number left in the X-register. The effect is simply to separate
two sequentially entered numbers.
Using a Number Twice in a Row. You can use the replicating feature of
to other advantages. To add a number to itself, key in the number
E
and press
E+
Filling the Stack with a Constant. The replicating effect of
together with the replicating effect (from T into Z) of stack drop, allows
you to fill the stack with a numeric constant for calculations.
Example: Constant, Cumulative Growth. The annual sales of a small
hardware company are projected to double each year for the next 3
years. If the current sales are $84,000, what are the annual sales for
each of the next 3 years ?
1.
Fill the stack with the growth rate (2
2. Key in the current sales in thousands (84).
separates two numbers keyed in one after the
5 ＋ 6 ：
a (lost) b (lost)
b
c
d
5
E
Lift
.
c c
d d
5 5
5 6
6
Lift No lift
EEE
E: RPN: The Stack 271
c
c
d
11
+
Drop
,
E
).