Welcome to the RAPTOR home page

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RAPTOR is a flowchart-based programming environment, designed specifically to help students visualize their algorithms and avoid syntactic baggage.  RAPTOR programs are created visually and executed visually by tracing the execution through the flowchart.  Required syntax is kept to a minimum.  Students prefer using flowcharts to express their algorithms, and are more successful creating algorithms using RAPTOR than using a traditional language or writing flowcharts without RAPTOR.

Click here to see a picture of RAPTOR.  For a paper describing the use of RAPTOR in a general education course, click here. Heres another paper from the Global Chinese Conference on Computers in Education (GCCCE) 2011. (Midwest Instruction and Computing Symposium) Evaluating the Use of Flowchart-based RAPTOR Programming in CS0. American Society for Engineering Education RAPTOR - A Vehicle to Enhance Logical Thinking.

RAPTOR is referenced in (at least) Starting Out with Programming Logic & Design (Tony Gaddis), Prelude to Programming Concepts and Design (Venit and Drake), School-based ICT (Longman Computer Course for Junior Secondary) (English and Chinese versions), and Introduccin a la programacin, Algoritmos y su implementacin en VB.NET, C#, Java y C++, and the following books from Tsinghua University Press (Chinese -- Visualized Computing 2012, Visualized Computing based On RAPTOR case tutorial 2014, RAPTOR programming case tutorial)


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Where/how are you using RAPTOR?   I keep a list of what schools and universities are using RAPTOR and for what class.  This helps me plan future advancements.  Please email me and let me know.

Newest Installer (digitally signed on 10/1/2016 -- hopefully this will help with Windows Defender issues!)

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Based on .NET Framework 4.5. XP users may need to use an older installer (2014 or earlier).

Portable Version

John Meir from Midlands Tech created a Portable App version (PortableApps.com). This allows RAPTOR to be used from a USB key or similar without installing. You can download the portable version here. This version is from 2012.

FALL 2015 VERSION (Updated 15 August 2015)

First version based on .NET Framework 4.5

FALL 2014 VERSION (Updated 22 April 2015)

Fixed issue with color White

Fixed issue where users able to create Subcharts in OO mode

Other minor updates to include new signed installer

NOTE! The installer was signed with a US Department of Defense certificate. You can get the root certificates from DoD Class 3 PKI Root Certificates. If you have difficulty with the signed installer, you can also try the unsigned installer.

Windows 8 users

You may need to enable .NET 3.5. See instructions here.

SPRING 2012 VERSION (Updated 13 September 2012)

13 September version fixes anomalies with set_precision

27 August version hopefully fixes Print Dialog on Windows 7 64-bit

Minor updates to Java code generation. Update to how RAPTOR OO mode handles recursive functions. Download here

KNOWN ISSUE: RAPTOR OO-mode does not correctly handle all recursive functions.

SPRING 2011 VERSION (Updated 18 May 2011)

You can get the Spring 2011 version (4.0.4) of RAPTOR from here (right-click and choose "save target as").  NOTE: See above on certificates. Also requires .NET 2.0 Framework.  Files generated in this version (except those in OO mode) can be opened with the Summer 2007 version.

NEW INSTALLER!  This installer has been tested on Windows XP SP3 (32 bit), Windows XP Tablet PC (32 bit), Windows 7 Professional (32 and 64 bit) and Vista Business (64 bit).  This installer should eliminate many installation bugs from the Microsoft Ink DLL.


     Can now have plugin methods that return String.

     Input and Output dialogs no longer have radios to select text vs. expression.  This seemed more confusing than helpful.  Now all prompts/outputs are expressions.  Be sure to use "" (quotation marks).

     Set_Precision(digits) allows you to specify how many digits of precision will be in an output.  Set_Precision(2) is useful for currency.  Set_Precision(-1) returns to the default floating precision (4 significant figures).

     Redirect_Output_Append allows you to redirect output to a file, appending the data on the end.

     Current_Year, Current_Month, Current_Day, Current_Hour, Current_Minute, Current_Second, Current_Millisecond -- new time functions

     Current_Time -- returns the number of milliseconds since January 1, 1990 (midnight).

Link to Older Versions

Other Operating Systems

RAPTOR is written in a combination of C# and A# (a port of Ada to the .NET Framework) and is only supported on Windows.  We have experimented with Mono Ubuntu.  We were able to get RAPTOR running on Ubuntu with some features removed.  Here's a zip with all of the files in case you want to try it. The most frequent question I get is if there is a Mac version. We don't have time to develop one, but I've heard that Wine may let you run the Windows version on a Mac.

About Modes

Did you know RAPTOR has modes?  By default, you start in Novice mode.  Novice mode has a single global namespace for variables.  Intermediate mode allows you to create procedures that have their own scope (introducing the notion of parameter passing and supports recursion).  Object-Oriented mode is new (in the Summer 2009 version)

About Loops

A common question is about RAPTOR loops being "backwards" from Java. We believe this form of loop logic is more intuitive to beginners; however, if you wish to match the semantics of Java loops, i.e. exit when the condition is false instead of when the condition is true, set the registry entry HKEY_LOCAL_MACHINE\Software\Raptor\reverse_loop_logic to true.

RAPTOR is Free!

RAPTOR is freely distributed as a service to the CS education community.  RAPTOR was originally developed by and for the US Air Force Academy, Department of Computer Science, but its use has spread and RAPTOR is now used for CS education in over 30 countries on at least 4 continents. Martin Carlisle is the primary maintainer, and is a professor at Carnegie Mellon University.

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     Introduction to Algorithmic Thinking

     Introduction to RAPTOR

     RAPTOR Syntax Guide

     Control Structures

     Analyzing Requirements

     Process Abstraction and RAPTORGraph

     RAPTOR Subcharts and Procedures

     Introduction to Array Variables

     Functional Decomposition

     Older handouts

o    Introduction to RAPTOR programming

o    Graphics programming with RAPTOR

o    Programming loops and selections

o    Arrays

OO Mode Handouts

Below handouts are by Elizabeth Drake, edited from Appendix D of her book, Prelude to Programming: Concepts and Design, 5th Edition, by Elizabeth Drake and Stewart Venit, Addison-Wesley, 2011. Linked here with author's permission.

     RAPTOR OO Programming Mode

     RAPTOR Data Files

     Combined RAPTOR Data Files/OO Mode

For Faculty

     Implementing a RAPTOR test server

     Creating plugin functions and procedures

     Create your own code generator

     Easter Eggs


     Terry Wilson

     Martin C. Carlisle

     Jeff Humphries

     Jason Moore


Comments, suggestions, and bug reports are welcome. If you have a comment, suggestion or bug report, send an email to Martin Carlisle.


David Cox has put together a user forum at http://raptorflowchart.freeforums.org. This provides a place for users to exchange ideas, how tos, etc. Note however, that feedback for the author should be sent by email rather than posting on this forum.

Youtube Videos

Randy Bower has some YouTube tutorials at http://www.youtube.com/user/RandallBower. You can also search YouTube for "RAPTOR flowchart".


The UML designer is based on NClass, an open-source UML Class Designer.  NClass is licensed under the GNU General Public License.  The rest of RAPTOR, by US Air Force policy, is public domain.  Source is found here.  RAPTOR is written in a combination of A# and C#.  Unfortunately, I don't have the time to provide support on compilation issues.