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Designed byDr. Martin C. Carlisle, Lt Col Ricky Sward, Maj Jeff Humphries
First appeared2004; 20 years ago (2004)
PlatformCommon Language Infrastructure
LicenseGNU General Public License

A# is a port of the Ada programming language to the Microsoft .NET platform. A# is freely distributed by the Department of Computer Science at the United States Air Force Academy as a service to the Ada community under the terms of the GNU General Public License.

AdaCore took over this development in 2007, and announced "GNAT for .NET", which is a fully supported .NET product with all of the features of A# and more.[1] As of 2021, A# has fallen dramatically in popularity and is considered by some to be a dead language (there are no known users or implementations).[2][unreliable source?]


hello world

with Ada.Text_IO;
use Ada.Text_IO;
procedure Hello_Dotnet is
 Put_Line(Item => Hello .NET world!”);
end Hello_Dotnet;



  1. ^ Cited by Martin Carlisle (USAFA) and see also Archived 2007-10-28 at the Wayback Machine
  2. ^ Developer, Website (2021-03-10). "The Mysterious Existence of A#". Medium. Retrieved 2021-06-22.
  3. ^ "A#: Multilanguage Programming with Ada in .NET". Retrieved July 1, 2023.