xkcph2017 / CalC

A calculator mostly written in C, then PureBasic for the GUI

Calculator CalC

This is a simple console app calculator that supports most of the functions that one can find in a scientific calculator.

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Furthermore, to demonstrate creating GUI in another language that will communicate with this program, Mong Alvarez Jr. decided to use PureBasic for the GUI. But there is so much to be done yet. Mong Alvarez Jr. does not have enough time to finish this (as always). This is just the initial effort.

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In component-based approach, software developers need only to know the behavior of a component and how they would interact with that component. One good example is Java Bean.

But here, the only interface is the command line argument and that is enough so that PureBasic can interact with this program. But C and PureBasic were not meant for component-based build, yet in situations like this, software developers can agree on how each component should communicate with one another.

Compile and Create Executables

Compile with,

gcc -std=c99 -o calc calc.c helpers.c -lm

Run with,

./calc [OPTIONS] <EXPRESSION>...

or in Windows OS,

calc.exe [OPTIONS] <EXPRESSION>...

Obviously, the expressions are expected to be quoted within single quotation marks to prevent bash/shell from parsing them.

In Windows OS, you can just type the arguments without space/s to be interpreted as single expression or can be inside double quotation marks.

PureBasic Compile and Create Executable

As usual, in PureBasic, it is very easy to compile the calc.pb using the PureBasic IDE.

The compiled file of calc.pb used an icon that is included here. This is the favorite icon of Mong Alvarez Jr. that he created and is the icon being used for his apps:

Options

The following flags can be used:

1. -d, consider all angles to be degrees. Results are also in degrees.
2. -n, print results of each expressions in a new line instead of separating them by ;.
3. -h (or) --help, print help and exit.

Expressions

CalC supports multiple expressions in a single call.

For example,

./calc '3.4' 'atan(1/0) - 3.14159265358979323846 * sqrt 3'

The result of each expression is printed either in the same line separated by semicolons or in separate lines if the -n flag is used.

For example, the output of the above is:

3.4;-3.870601766

with -n flag,

3.4
-3.870601766

Features

Operators

The following operators are supported:

+ --> addition
- --> subtraction
* --> multiplication
/ --> division
% --> modulo
! --> factorial
^ --> exponent

Unary + and - are also supported. ~ and _ operators act as aliases for unary - and +, respectively.

The $ (dollar) operator can be used to refer to the result of a particular sub-expression. Sub-expression are created using the , (comma) operator. For example,

./calc '7 - 5, sin$1, log($1 - -$2)'

The expression has three sub-expression.

$1 = 7 - 5
$2 = sin$1 = sin(7 - 5)
$3 = log($1 - -$2) = log(7 - 5 - -sin(7 - 5))

The results of all three expressions is printed in comma-separated format.

2,0.9092974268,0.4637881228

Functions

The following functions are supported:

sin, cos, tan, asin, acos, atan, sinh, cosh, tanh, asinh, acosh, atanh, log (base 10), ln (base e), exp (e raised), floor, ceil, round, sqrt, abs, sgn

sgn returns 1 if positive, -1 if negative else 0.

Trignometric function may have infinite precision related issues.

For example,

./calc 'sin pi' 'cos pi'

results in,

7.338823075E-05;-0.9999999973

The actual values being 0 and -1. pi here is a symbolic constant.

Symbolic Constants

The following symbolic constants are supported:

pi    -->  3.14159265358979323846
e     -->  2.7182818284590452354
g     -->  1.6180339887498948482
inf   -->  infinity
rand  -->  random double in the range (0, 1). (ironic, i know...)

For example,

./calc 'atan inf' 'rand, sin $1, cos($2 - $1)' '-+_+_++_--~---~+_rand'

will result to:

1.570796327;0.4473471527,0.4325752577,0.9998908975;0.6601152609

TO DO

1. add support for complex numbers
2. add implicit multiplication: (sin 3 cos 4 --> sin 3 * cos 4 or (9 - 4) (sin 3) --> (9 - 4) * (sin 3))
3. add symbolic mathematics

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For the GUI written in PureBasic:

• complete the necessary GUI rendering for all the features from the original CalC program particularly the scientific calculator

• create an algorithm so that measuring and adjusting the buttons and panels would be easy enough

Take note, Mong is determined to do all these things, but he is always busy.

LICENSE

CalC was originally licensed under MIT by Vivek Kannan. The copy of that license is retained at this repo.

Also, Mong Alvarez Jr. licensed this repo under MIT.