HP 33s - Manual (Page 205)

Programming Techniques 13–21
The Indirect Address, (i)
Many functions that use A through Z (as variables or labels) can use ” to refer to
A through Z (variables or labels) or statistics registers indirectly. The function ”
uses the value in variable i to determine which variable, label, or register to
address. The following table shows how.
If i contains: Then (i) will address:
± 1 variable A or label A
.
.
.
.
.
.
±26 variable Z or label Z
±27 variable i
±28 n register
±29 Σx register
±30 Σy register
±31 Σx 2
register
±32 Σy 2
register
±33 Σxy register
≥34 or ≤–34 or 0 error: # 1 1L2 2
Only the absolute value of the integer portion of the number in i is used for
addressing.
The INPUT(i) and VIEW(i) operations label the display with the name of the
indirectly–addressed variable or register.
The SUMS menu enables you to recall values from the statistics registers. However,
you must use indirect addressing to do other operations, such as STO, VIEW, and
INPUT.
The functions listed below can use (i) as an address. For GTO, XEQ, and FN=, (i)
refers to a label; for all other functions (i) refers to a variable or register.