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FLVIZ - DFA simulator

Build status

FLVIZ stands for "Formal Languages Visualizer". It is a Windows GUI program which reads a configuration file, and based on its content creates a visualization of a state machine (graph), and lets you apply a stimulus (vocabulary) and see the state transitions happen dynamically.


It was originally written in 2009 during my "Formal Languages" class which was a part of my M.Sc CS curriculum. The biggest challenge was getting it on time and making it work under Windows, since it was written in about 3 days on FreeBSD and then quickly ported. You can see what I mean if you glance at the release directory.

Created for Windows XP with SP 3 and based on QT Creator and QT4 library, it hasn't been build/used since I finished the class. In 2015 I have updated it: by using I converted it to Qt5 library and made it work on Windows Server 2012.

During "Formal languages" class we were provided the state machine input file. The format isn't something I designed and is very imperfect.


  • Windows system. Originally XP, then ported to Windows Server 2012. I suspect any decent Windows version should be fine.
  • Qt Creator (tested with Qt 5.5)
  • MinGW GCC (installation as a part of Qt)
    • I haven't tested building it with Microsoft Visual C++

All libraries are present in the repo, so deployment straight after compilation should be possible.

Build instructions

For convenience, build script build.bat is present in the repository. To build, run:


Please note this script may need to be adjusted if you end up building with anything else but Qt 5.5.

Convenience tools for AppVeyor

If you clone the repository and also decide to use Appveyor for remote testing/work, you may want to run:


Which will install both Vim editor and ConEmu, which are convenience tools for development.

Data format

Data format was provided in a class. It's not great. Sample data format is as follows:

 filename   line             data
data.1.txt |  1 |		5 3 2
data.1.txt |  2 |
data.1.txt |  3 |		<tablica wejsciowa ASD>
data.1.txt |  4 |		0 1 e
data.1.txt |  5 |		1 f f 2
data.1.txt |  6 |		2 3 f f
data.1.txt |  7 |		3 f f 2
data.1.txt |  8 |		4 f 5 f
data.1.txt |  9 |		5 f f f
data.1.txt | 10 |
data.1.txt | 11 |		<tablica stanow koncowych>
data.1.txt | 12 |		3 4

Empty spaces or lines don't matter. For convenience of discussion, I'm mentioning line numbers for reference below. f means empty state.

TODO: understand state indexing. My original comment stated states are indexed from 0, which I believe referred to the implementation.

Data format explanation

  • Line (1), intro:

    • 5 states
    • 3 letters in the alphabet
    • 2 end states
  • Line (3), magic pragmas:

    • <tablica wejsciowa ASD> dla automatu ASD
    • <tablica wejsciowa ASN> dla automatu ASN
    • TODO: I don't remember what these were all about.
  • Line (4):

    • Alphabet available to this program
  • Lines (5--9):

    • first column means state name, if I'm not mistaken
    • consecutive columns define transitions if one of the alphabet inputs is applied.
    • TODO: example needed. Must confirm.
  • Line (11), magic pragma:

    • List of end states.


There are some example data files in the dane folder.



FLVIz - Finite Automata Simulator written in QT/Graphviz





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