HP 35s Scientific Calculator - Manual (Page 73)

Storing Data into Variables 3-9
Example:
The Variables "I" and "J"
There are two variables that you can access directly: the variables I and J. Although
they store values as other variables do, I and J are special in that they can be used
to refer to other variables, including the statistical registers, using the (I) and (J)
commands. (I) is found on the
 key, while (J) is on the  key. This is a
programming technique called indirect addressing that is covered under “Indirectly
Addressing Variables and Labels” in chapter 14.
Keys: Display: Description:

A  Stores 12 in variable A.
 _ Displays x.
A  Exchanges contents of the X–register
and variable A.
A  Exchanges contents of the X–register
and variable A.
A
12
A
3
T
t
T
t
Z
z
Z
z
Y
y
Y
y
X
3 A
X
12