ccal

A flexible calculator that ships with a Windows GUI front end and a cross-platform CLI. Both layers share the same C parser so complex expressions behave identically.

Requirements:

All platforms require the GNU compiler gcc.

Windows note: the easiest path to gcc is through Cygwin.

Apple

The CLI can be compiled on macOS. Install the toolchain via Homebrew:

brew install gcc

Linux

The CLI runs on common Linux distributions. Install the essentials with apt:

sudo apt update
sudo apt install build-essential

To write changes to help.txt, you'll need xxd.

sudo apt install xxd

Windows

First, use Windows Package Manager (winget) to install Cygwin:

winget install Cygwin.Cygwin

Next, download the Cygwin installer setup-x86_64.exe. Move it to /usr/bin (or another location on your PATH) so it can be invoked from the command prompt, then install gcc:

setup-x86_64.exe -P gcc-core

To write changes to help.txt, you'll need xxd.

setup-x86_64.exe -P xxd

Follow the installer prompts until you reach Select Packages.

If gcc-core is not listed, search for it, mark it for installation, then continue.

Compile Command Line Tool

The CLI builds on macOS, Linux, and Windows. Compile the core engine:

gcc ccal.c -o ccal.exe

To include updates to help.txt, regenerate the header before compiling:

xxd -i help.txt > help.h

This embeds the latest help text in the executable.

Compile GUI:

Clone the repository

Start by cloning the code and switching into the working directory:

git clone https://github.com/jhauga/ccal.git
cd ccal

Simplest build (no resources)

Compile the GUI without bundling extra resources:

gcc -DBUILDING_GUI ccal.c ccal_gui.c -o ccal_gui.exe -mwindows

Build with resources (icon, etc.)

First compile the resource script into a COFF object:

windres ccal_gui.rc -O coff -o ccal_gui.res

Then link the GUI, resource object, and core engine together:

gcc -DBUILDING_GUI ccal_gui.c ccal.c ccal_gui.res -o ccal_gui.exe -mwindows

GUI Usage (Windows)

1. Launch ccal_gui.exe from Explorer or the command line.
2. Enter expressions using the on-screen buttons or the keyboard.
3. Press Enter or click = to evaluate.
4. Press d to clear the current expression and result.
5. Use Ctrl + C to copy the result to the clipboard.

Comma formatting is applied automatically while you type, and backspace/delete skip over commas so numbers stay nicely grouped.

Command Line Usage

To use the CLI, pass digits, arithmetic operators, and nesting characters ((, ), {, }, [, ]) separated with spaces.

Important: use x instead of *, and p instead of ^, unless you pass -q/--quote.

Acceptable Arithmetic Operators

+  -> addition
-  -> subtraction
/  -> division
x  -> multiplication
*  -> multiplication (use -q/--quote)
p  -> exponentiation (power of)
^  -> exponentiation (use -q/--quote)

Command Line Use Examples

To use the command line tool either input all elements of the equation separated with a space character, or use the quote option -q, --quote which does not require elements to be separated with a space character.

If nested brackets cause argument parsing issues, escape them or wrap the expression in quotes. Square brackets generally require the fewest escapes.

Add two numbers:

> ccal 1 + 1
> 2

Perform a complex equation:

> ccal [ [ 34 x 11 ] / [ 10 - 5 ] ] - [ 4 x 53 x [ 30 / 10 ] ]
> -561.2

Without -q/--quote, order of operations can break across spaced tokens, so expressions like:

> ccal [ [ 34 x 11 ] / [ 10 - 5 ] ] - [ 4 x 53 x [ 30 / 10 ] + [ 2 x [ 40 - 20 ] ] ] / [ 8 x 6 x [ 12 / 2 ] + 4 ]
> -2.058904109589041

will evaluate incorrectly (the correct answer is 72.4849). Use -q/--quote—recommended—or add explicit parentheses to force the intended precedence:

Quote option (recommended):

> ccal -q "[[34x11]/[10-5]]-[4x53x[30/10]+[2x[40-20]]]/[8x6x[12/2]+4]"
> 72.48493150684931

Manual grouping:

> ccal [ [ 34 x 11 ] / [ 10 - 5 ] ] - [ [ [ 4 x 53 ] x [ 30 / 10 ] + [ 2 x [ 40 - 20 ] ] ] / [ 8 x 6 x [ 12 / 2 ] + 4 ] ]
> 72.48493150684931

Both approaches return the correct value.

Terminals treat commas as separators, so wrap comma-separated numbers in quotes or use -q/--quote. Instead of:

> ccal 1,000 - 1
> Error: Invalid expression

Use the quote option or wrap comma numbers manually:

Quote option:

> ccal --quote "2,000-1,000"
> 1000

Manual quoting:

> ccal "2,000" - "1,000"
> 1000

to get the correct calculation.

Calculate Exponentiation

To calculate exponentiation, use p as the operator. With -q/--quote, you can also use ^.

> ccal 2 p 2
> 4

> ccal --quote "2^2"
> 4