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.

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* ''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 ...

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.

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

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Notation

Variable handling

See also

References

External links