HP 35s HP 35s scientific calculator - User Guide - Page 47

RPN: The Automatic Memory Stack, What the Stack Is - programs free

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2 RPN: The Automatic Memory Stack This chapter explains how calculations take place in the automatic memory stack in RPN mode. You do not need to read and understand this material to use the calculator, but understanding the material will greatly enhance your use of the calculator, especially when programming. In part 2, "Programming", you will learn how the stack can help you to manipulate and organize data for programs. What the Stack Is Automatic storage of intermediate results is the reason that the HP 35s easily processes complex calculations, and does so without parentheses. The key to automatic storage is the automatic, RPN memory stack. HP's operating logic is based on an unambiguous, parentheses-free mathematical logic known as "Polish Notation," developed by the Polish logician Jan Łukasiewicz (1878-1956). While conventional algebraic notation places the operators between the relevant numbers or variables, Łukasiewicz's notation places them before the numbers or variables. For optimal efficiency of the stack, we have modified that notation to specify the operators after the numbers. Hence the term Reverse Polish Notation, or RPN. The stack consists of four storage locations, called registers, which are "stacked" on top of each other. These registers - labeled X, Y, Z, and T - store and manipulate four current numbers. The "oldest" number is stored in the T- (top) register. The stack is the work area for calculations. RPN: The Automatic Memory Stack 2-1

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RPN: The Automatic Memory Stack
2-1
2
RPN: The Automatic
Memory Stack
This chapter explains how calculations take place in the automatic memory stack in
RPN mode.
You do not need to read and understand this material to use the
calculator
, but understanding the material will greatly enhance your use of the
calculator, especially when programming.
In part 2, "Programming", you will learn how the stack can help you to manipulate
and organize data for programs.
What the Stack Is
Automatic storage of intermediate results
is the reason that the HP 35s easily
processes complex calculations, and does so without parentheses. The key to
automatic storage is the
automatic, RPN memory stack
.
HP's operating logic is based on an unambiguous,
parentheses–free
mathematical
logic known as "Polish Notation," developed by the Polish logician Jan
Ł
ukasiewicz
(1878–1956).
While conventional algebraic notation places the operators
between
the relevant
numbers or variables,
Ł
ukasiewicz's notation places them
before
the numbers or
variables. For optimal efficiency of the stack, we have modified that notation to
specify the operators
after
the numbers. Hence the term
Reverse Polish Notation
, or
RPN.
The stack consists of four storage locations, called
registers
, which are "stacked" on
top of each other. These registers — labeled X, Y, Z, and T — store and manipulate
four current numbers. The "oldest" number is stored in the T– (
top
) register. The stack
is the work area for calculations.