GNOME Calculator, formerly known as gcalctool, is the
software calculator
A software calculator is a calculator that has been implemented as a computer program, rather than as a physical hardware device.
They are among the simpler interactive software tools, and, as such, they provide operations for the user to sele ...
integrated with the
GNOME desktop environment
A gnome is a mythological creature and diminutive spirit in Renaissance magic and alchemy, first introduced by Paracelsus in the 16th century and later adopted by more recent authors including those of modern fantasy literature. Its character ...
. It is programmed in
C and
Vala and part of the
GNOME Core Applications.
Views
* ''Basic'' – interface for basic arithmetic, resembling a
desk calculator
An electronic calculator is typically a portable electronic device used to perform calculations, ranging from basic arithmetic to complex mathematics.
The first solid-state electronic calculator was created in the early 1960s. Pocket-sized ...
.
* ''Advanced'' – an interface with scientific functions, and support for custom variables.
* ''Financial'' – financial calculation and
currency conversion.
* ''Programming'' – a view with
bit manipulation operators and
radix
In a positional numeral system, the radix or base is the number of unique digits, including the digit zero, used to represent numbers. For example, for the decimal/denary system (the most common system in use today) the radix (base number) is t ...
conversion.
* ''Keyboard'' – most of the space is taken up by the output, with no on-screen buttons. Supports currency and
unit conversion.
Notation
The GNOME calculator uses the common
infix notation
Infix notation is the notation commonly used in arithmetical and logical formulae and statements. It is characterized by the placement of operators between operands—" infixed operators"—such as the plus sign in .
Usage
Binary relations a ...
for
binary function
In mathematics, a binary function (also called bivariate function, or function of two variables) is a function that takes two inputs.
Precisely stated, a function f is binary if there exists sets X, Y, Z such that
:\,f \colon X \times Y \rightar ...
s, such as the four basic arithmetic operations. Unlike many other calculators, it uses
prefix notation, not
postfix notation
Reverse Polish notation (RPN), also known as reverse Łukasiewicz notation, Polish postfix notation or simply postfix notation, is a mathematical notation in which operators ''follow'' their operands, in contrast to Polish notation (PN), in whi ...
for
unary functions. So to calculate e.g. the
sine
In mathematics, sine and cosine are trigonometric functions of an angle. The sine and cosine of an acute angle are defined in the context of a right triangle: for the specified angle, its sine is the ratio of the length of the side that is oppo ...
of
one
1 (one, unit, unity) is a number representing a single or the only entity. 1 is also a numerical digit and represents a single unit of counting or measurement. For example, a line segment of ''unit length'' is a line segment of length 1. I ...
, the user must push the keys "sin", "1", "=" – not "1", "sin" as on many other calculators.
The decimal separator on the
number pad
A numeric keypad, number pad, numpad, or ten key,
is the palm-sized, usually-17-key section of a standard computer keyboard, usually on the far right. It provides calculator-style efficiency for entering numbers. The idea of a 10-key nu ...
is based on the general keyboard layout since version 3.12.3.
Variable handling
''Advanced'', ''Financial'', and ''Programming'' modes present features for storing and retrieving values labeled as variables. ''R'' is the symbol for ''variable'', used on GUI buttons ''←R'' (insert variable) and ''→R'' (assign variable).
Variable names are case-sensitive alphabetical string without spaces. Variable values are numerical strings.
Values are assigned to variable names by entering in the GUI text input/result field a variable name followed by 0 or more spaces, followed by the ''='' character, followed by 0 or more spaces, followed by either a numeric value or an existing variable name, e.g. "x = 2" or "result = subtotal" (if subtotal was already assigned a numeric value). A numeric value is assigned to the first variable name. If the value was entered as an existing variable name rather than as a numeric value, the existing variable's value is assigned to the first variable name. Assignment to a variable name that does not exist creates the new variable by name with the assigned value. The ''→R'' (assign variable) GUI button shows a popup menu of existing variables (and the current value of each), to which selected variable is assigned the current numeric value displayed in the calculator, just as if that variable name were entered in the GUI text field followed by a ''='' followed by the numeric value.
Entering a variable name into the GUI text field substitutes the variable value for the variable name when the expression in the GUI text field is evaluated (e.g. when the keyboard <Enter> button or the ''='' GUI button is pressed). The ''←R'' (insert variable) GUI button shows a popup menu of existing variables (and the current value of each); the selected variable name is inserted (appended) into the GUI text field.
Two predefined variables are available from the ''←R'' (insert variable) GUI button: ''ans'' and ''rand''. ''ans'' contains the last "answer" value calculated by the calculator as a result. ''rand'' contains a random value between 0.0 and 1.0 (the value is not displayed; a rand variable is evaluated in an expression when calculating a result).
Variable names and values persist between launch and quit of the application.
See also
*
Comparison of software calculators
This is a list of notable software calculators.
Immediate execution calculators (button-oriented)
Expression or formula calculators (command-line oriented)
See also
* Software calculator
* Calculator input methods
* Formula calculator
* C ...
*
KCalc
KCalc is the software calculator integrated with the KDE Gear. In the default view it includes a number pad, buttons for adding, subtracting, multiplying, and dividing, brackets, memory keys, percent, reciprocal, factorial, square, and x to the p ...
References
External links
*
{{GNOME
Software calculators
GNOME Core Applications
Software that uses GTK
Software that uses Meson
Free software programmed in C
Free software programmed in Vala