Calculator input methods: Difference between revisions

Revision as of 10:30, 4 May 2009

Revision as of 12:38, 4 May 2009

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A '''Button-operated calculator''' is a hardware or software calculator which is operated using buttons - as oposedopposed to a [[Formula calculator]] which is operated by entering formularsformulas with a keyboard.

== Mode of operations ==

There are variusvarious ways in which the in which a button-operated calculator might interpret key strokes.

=== Reverse Polish Notation (RPN) ===

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{{main|Reverse Polish Notation}}

In Reverse Polish Notation also known as '''Postfix notation''' all operations are entered after the peratnsoperands on which the operatinoperation is performed. Reverse Polish Notation is parenthesis-free which usualyusually leads to less button presses needed to perfomperform a operation. By the use of [[Stack_(data_structure)|stack]] one can enter formulaeformulas withouthwithout the need ofto rearangerearrange operands.

{| class="wikitable" border="1"

|+ Examples

! Formula

! Formular

! Key strokes

! Key stroke count

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|}

Note example 1 which is one of the few examples where Reverse Polish Notation does not use the fewest button presses - provided one does not rearangerearrange operants. If one would do so then onyonly 5 key strokes would be needed.

=== infix notation (without [[order of operations]]) ===

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{{main|Infix notation}}

Infix notation without [[order of operations]] is used by simple non -scientific calculators. With this mode the mathematical order of operations is not honored butand all operatins are operations are imediatelyimmediately execudedexecuted. Also advandedadvanced operations like √ or x² are entered after the operation.

{| class="wikitable" border="1"

|+ Examples

! Formula

! Formular

! Key strokes

! Key stroke count

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|}

From the first example one can see that it is nessesarynecessary to rearagerearrange operants in order to get the correct result.

=== infix notation (with [[order of operations]]) ===

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{{main|order of operations}}

Infix notation with [[order of operations]] where used by scientific calculators in from the 70th to the 90th. With this mode the mathematical order of operations is where honored but advandedadvanced operations like √ or x² where are still entered after the operation. This mode of operation has been replaced by [[#Direct_algebraic_logic_.28D.A.L..29|Direct algebraic logic]].

{| class="wikitable" border="1"

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This mode was used from the 80th to the 90th in BASIC programmable calculators and pocket computers.

In BASIC notation the formularformula is entered as it would be entered in BASIC <CODE>PRINT</CODE> command - the <CODE>PRINT</CODE> command itself beeinbeing optional. On pressing the ENTER the result would be displayed. Typing mistakes in the entered formularformula could be corrected using the same editor function as available when programming the calculator.

Some BASIC programmable [[Pocket computer|Pocket computers]] had dedicated trigonometric keys <ref>The picture of the [http://pocket.free.fr/html/casio/fx-880p_e.html FX-880P] show sin, cos and tan keys on the second row right hand side.</ref> hence the keystroke count is given as a range. Some BASIC programmable [[Pocket computer|Pocket computers]] could also be operate in arithmetic logic.

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{| class="wikitable" border="1"

|+ Examples

! Formula

! Formular

! Key strokes

! Key stroke count

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{| class="wikitable" border="1"

|+ Examples

! Formula

! Formular

! Key strokes

! Key stroke count