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This article introduces you the example analysis of Qalculate calculator, the content is very detailed, interested friends can refer to, hope to be helpful to you.

Qalculate! Is a multi-functional cross-platform desktop calculator.

It is simple to use, but provides features and versatility that are usually reserved for complex mathematical packages, as well as useful tools to meet day-to-day needs, such as currency conversion and percentage calculations. Features include a large number of customizable functions, unit calculations and conversions, physical constants, symbolic calculations (including integrals and equations), arbitrary precision, uncertainty propagation, interval arithmetic, graphics and user-friendly interfaces (GTK + and CLI) libraries.

Features include:

A graphical user interface implemented using KDE or GTK +-2.0 and Glade XML.

Flexible expression input and separate result display.

Displays whether the results are accurate.

Small, not small mode.

Practical menus give you quick access to all advanced features.

Computational history.

Optional traditional calculator button.

Dialog box for managing and easily accessing functions, variables and units (quick conversion).

User-friendly function dialog box with description and parameter entries.

Create / edit functions, variables and units.

Easily edit matrices and vectors.

Easy to connect to gnuplot.

A separate window that can be quickly converted between digital cardinals.

The periodic table.

Small stand-alone utility for base, currency and unit conversion.

Other text-based interfaces with full functionality.

Enhanced completion.

Metamodel.

Calculation and parsing: basic operations and operators: +-* / ^ E () & & | |! > =. Fault-tolerant parsing of strings: log 5bind 2.5 (3) + (2 (3 + 5 = ln (5) / (2.5 * 3) + 2 * (3 + 5). Expressions can contain any combination of numbers, functions, units, variables, vectors, and matrices. Plural and infinite numbers are supported. Supports all numeric bases, time formats and Roman numerals from 2 to 36. Disable the function of functions, variables, units or unknown variables to reduce confusion: for example. When you don't want (a + b) ^ 2 to represent (are + barn) ^ 2 but ("a" + "b") ^ 2. Controllable implicit multiplication. Matrix and vector, and related operations (determinant, etc.). Detailed error message. Arbitrary precision. RPN mode.

The results show that all cardinals from 2 to 36 are supported, as well as hexadecimal numbers, time format and Roman numerals. Many custom options: precision, maximum / minimum.

Decimals, multiplication symbols, etc. Precise or approximate. Score: 4 + 6 * 2 = 1.333. = 4pm 3 = 1 + 1max 3.

Symbolic calculation: ex. (X + y) ^ 2 = x ^ 2 + 2xy + y ^ 2; 4 apples + 3 oranges. Decompose and simplify. Differentiation and integration. Most equations and inequalities can be solved. Customizable assumptions give different results (for example, ln (2x) = ln (2) + ln (x) if x is assumed to be positive).

Functions: all common functions: sine, logarithm, etc. Ln 5 = 1.609; sqrt (tan (20)-5) = sqrt (- 2.76283905578). Many statistics, finance, geometry and more functions (about 200). If..then..else functions, optional parameters and more features for flexible function creation. You can easily create, edit and save to a standard XML file.

Units: all SI units and prefixes (including binary), as well as imperial and other units are supported. Automatic conversion: ft + yd + m = 2.2192 m. Implicit conversion: 5m / s to mi / h = 11.18mph. Intelligent conversion: can automatically convert 5 kg * m / s ^ 2 to 5 newtons. Use daily exchange rate retrieval for currency conversion. Different forms of names: abbreviations, singular, plural (meters, meters). You can easily create, edit and save to a standard XML file.

Variables and constants: basic constant: pi,e. Many physical constants and elements. CSV files import and export. You can easily create, edit and save to a standard XML file. Flexible, can contain simple numbers, units, or entire expressions. Datasets with objects and related properties have a database-like structure.

Drawing: using gnuplot. You can draw functions or data (matrices and vectors). Can save the plot as PNG images, postscript, etc.

Several custom options.

This is the end of the sample analysis of the Qalculate calculator. I hope the above content can be of some help and learn more knowledge. If you think the article is good, you can share it for more people to see.

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