Creating a calculator application that provides both basic and more complex mathematical operations and supports number representation in different bases (decimal, binary, etc.). For this task, I use a well-known JavaScript library called math.js as calculation engine. Math.js features a flexible expression parser with support for symbolic computation, comes with a large set of built-in functions and constants, and offers an integrated solution to work with different data types like numbers, big numbers, complex numbers, fractions, units, and matrices.
- Input and Output fields– the application provides the option to input the numeric values from keyboard. It also displays a list of the expressions along with their results. One click in one expression will write in input field.
- C, CE and DEL buttons– allow to delete the current input, erase the memory and delete the last digit/operator from the user input respectively.
- Equals sign button– starts the computation.
- Number buttons, parethesis buttons, decimal mark button– allow to input numeric values without using keyboard, include hexadecimal values as well. Keyboard could also be used.
- Basic maths operation buttons– include addition, multiplication, subtraction, division and modulo operations.
- Numeric base option– allows the user to choose in which numeric base the numbers are represented. Number buttons are enabled / disabled accordingly to the current base selected (e.g. with binary numbers, only 1 and 2 are enabled). Input values also changes when calculation base is changed.
- Advanced maths operation buttons– include sinus, cosinus, exponential function, logarithm with the base of 2 and natural logarithm. User can choose whether the advanced operations are displayed or hidden.
- Edit menu with options to copy from both fields and paste to the input field.
- Help section with credits about the application and an manual of use. This will show the documentation for the math.js library for advance input use.
- The calculator has memory storing the result of the last computation.
- The next computation can use the value in memory as its first operand.
- The application provides different modes of use depends on the level of the user: a noob mode with basic use; a guided mode with restricted input; and an advance mode with free input, which will help us to take real advantage of calculation engine math.js
- User is able to provide input expressions from the keyboard. The application checks the format and ensure the correctness of the user input. A warning should be shown in case of incorrect input.
- Angles can be expressed in degrees or radians.
- Main class is called CalcDemo.java. Math.js is obtained by internet.
Project can be compiled and executed by the next commands in root project folder:
$ ant
$ java -jar dist/xmonte03.jar
