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Menu Learn Documentation Language Reference Library Reference Command-line Reference Feature Overview Articles Downloads Packages Community Blog Orgs using D Twitter Calendar Forums IRC Community Discord Wiki GitHub Issues Get involved Contributors Foundation Security Team Donate Sponsors Resources Tour Books Tutorials Tools Editors IDEs run.dlang.io Visual D Acknowledgments D Style Glossary Sitemap Search Entire Site Language Library Forums go Report a bug If you spot a problem with this page, click here to create a Bugzilla issue. Improve this page Quickly fork, edit online, and submit a pull request for this page. Requires a signed-in GitHub account. This works well for small changes. If you'd like to make larger changes you may want to consider using a local clone. D is a general-purpose programming language with static typing, systems-level access, and C-like syntax. With the D Programming Language , write fast, read fast, and run fast. Fast code, fast. Downloads Latest version: 2.092.0 – Changelog your code here Got a brief example illustrating D? Submit your code to the digitalmars.D forum specifying "[your code here]" in the subject. Upon approval it will be showcased here on a random schedule. Compute average line length for stdin The D programming language Modern convenience. Modeling power. Native efficiency. void main() { import std.range, std.stdio; auto sum = 0.0; auto count = stdin.byLine .tee!(l => sum += l.length).walkLength; writeln( "Average line length: " , count ? sum / count : 0); } Round floating point numbers 2.4 plus 2.4 equals 5 for sufficiently large values of 2. import std.algorithm, std.conv, std.functional, std.math, std.regex, std.stdio; alias round = pipe!(to! real , std.math.round, to!string); static reFloatingPoint = ctRegex! `[0-9]+\.[0-9]+` ; void main() { // Replace anything that looks like a real // number with the rounded equivalent. stdin .byLine .map!(l => l.replaceAll!(c => c.hit.round) (reFloatingPoint)) .each!writeln; } Sort lines Mercury Venus Earth Mars Jupiter Saturn Uranus Neptune import std.stdio, std.array, std.algorithm; void main() { stdin .byLineCopy .array .sort!((a, b) => a > b) // descending order .each!writeln; } Sort an Array at Compile-Time void main() { import std.algorithm, std.conv, std.stdio; "Starting program" .writeln; // Sort a constant declaration at Compile-Time enum a = [ 3, 1, 2, 4, 0 ]; static immutable b = sort(a); // Print the result _during_ compilation pragma (msg, text( "Finished compilation: " , b)); } Invoke external programs void main() { import std.exception, std.stdio, std.process; auto result = [ "whoami" ].execute; enforce(result.status == 0); result.output.write; } Print hex dump void main() { import std.algorithm, std.stdio, std.file, std.range; enum cols = 14; // Split file into 14-byte chunks per row thisExePath.File( "rb" ).byChunk(cols).take(20).each!(chunk => // Use range formatting to format the // hexadecimal part and align the text part writefln! "%(%02X %)%*s %s" ( chunk, 3 * (cols - chunk.length), "" , // Padding chunk.map!(c => // Replace non-printable c < 0x20 || c > 0x7E ? '.' : char (c)))); } Start a minimal web server #!/usr/bin/env dub /+ dub.sdl: dependency "vibe-d" version="~>0.8.0" +/ void main() { import vibe.d; listenHTTP( ":8080" , (req, res) { res.writeBody( "Hello, World: " ~ req.path); }); runApplication(); } Initialize an Array in parallel void main() { import std.datetime.stopwatch : benchmark; import std.math, std.parallelism, std.stdio; auto logs = new double [100_000]; auto bm = benchmark!({ foreach (i, ref elem; logs) elem = log(1.0 + i); }, { foreach (i, ref elem; logs.parallel) elem = log(1.0 + i); })(100); // number of executions of each tested function writefln( "Linear init: %s msecs" , bm[0].total! "msecs" ); writefln( "Parallel init: %s msecs" , bm[1].total! "msecs" ); } Sort in-place across multiple arrays void main() { import std.stdio : writefln; import std.algorithm.sorting : sort; import std.range : chain; int [] arr1 = [4, 9, 7]; int [] arr2 = [5, 2, 1, 10]; int [] arr3 = [6, 8, 3]; // @nogc functions are guaranteed by the compiler // to be without any GC allocation () @nogc { sort(chain(arr1, arr2, arr3)); }(); writefln( "%s\n%s\n%s\n" , arr1, arr2, arr3); } Count frequencies of all 2-tuples void main() { import std.stdio : writefln; int [ char [2]] aa; auto arr = "ABBBA" ; // Iterate over all pairs in the string and observe each pair // ('A', 'B'), ('B', 'B'), ('B', 'A'), ... // String slicing doesn't allocate a copy foreach (i; 0 .. arr.length - 1) aa[arr[i .. $][0 .. 2]]++; foreach (key, value; aa) writefln( "key: %s, value: %d" , key, value); } Tiny RPN calculator 2 3 3 4 + * * void main() { import std.stdio, std.string, std.algorithm, std.conv; // Reduce the RPN expression using a stack readln.split.fold!((stack, op) { switch (op) { // Generate operator switch cases statically static foreach (c; "+-*/" ) case [c]: return stack[0 .. $ - 2] ~ mixin ( "stack[&dollar - 2] " ~ c ~ " stack[&dollar - 1]" ); default : return stack ~ op.to! real ; } })(( real []).init).writeln; } Subtyping with alias this struct Point { private double [2] p; // Forward all undefined symbols to p alias p this ; double dot(Point rhs) { return p[0] * rhs.p[0] + p[1] * rhs.p[1]; } } void main() { import std.stdio : writeln; // Point behaves like a `double[2]` ... Point p1, p2; p1 = [2, 1], p2 = [1, 1]; assert (p1[$ - 1] == 1); // ... but with extended functionality writeln( "p1 dot p2 = " , p1.dot(p2)); } Support the D language D is made possible through the hard work and dedication of many volunteers, with the coordination and outreach of the D Language Foundation, a 501(c)(3) non-profit organization. You can help further the development of the D language and help grow our community by supporting the Foundation. Donate Learn More About The Foundation Lots of to our sponsors and contributors . Industry Proven D shines from low-level control to high-level abstraction Success stories What is D used for? Tweets by D_Programming News Stay updated with the latest posts in the Official D Blog from June 3, 2020: A Look at Chapel, D, and Julia Using Kernel Matrix Calculations by Dr. Chibisi Chima-Okereke. From May 14, 2020: Lomuto’s Comeback by Andrei Alexandrescu. Learn Take the Tour , explore major features in D, browse the quick overview , start with C or C++ background, and ask questions in the Learn forum . For a deeper dive into D check out books or videos such as Ali Çehreli's free book Programming in D . Community Discuss D on the forums , join the IRC channel , read our official Blog , or follow us on Twitter . Browse the wiki , where among other things you can find the high-level vision of the D Language Foundation . Documentation Refer to the language specification and the documentation of Phobos , D's standard library. The DMD manual tells you how to use the compiler. Read various articles to deepen your understanding. Contribute Report any bugs you find to our bug tracker . If you can fix an issue, make a pull request on GitHub . There are many other ways to help, too! Packages DUB is the package manager for D. Get started with DUB , and check out the available packages . Run Configure linting, formatting or completion for your favorite IDE , editor or use run.dlang.io to play and experiment with D code. Explore Learn about pragmatic D , the DStyle , common D idioms and templates , See what's coming upcoming with next version , explore D Improvement Proposals , and don't fear D's garbage collection . Fast code, fast. Write Fast D allows writing large code fragments without redundantly specifying types, like dynamic languages do. On the other hand, static inference deduces types and other code properties, giving the best of both the static and the dynamic worlds. void main() { // Define an array of numbers, double[]. // Compiler recognizes the common // type of all initializers. auto arr = [ 1, 2, 3.1...