Tutorial by Examples: d

You can create multiline code snippets by indenting each line with at least four spaces or one tab: #include <stdio.h> int main() { printf("Hello World!\n"); return 0; }

Some parsers allow code to be designated by adding three backticks before and after a section of code. ``` <p><em>This</em> is an HTML example!</p> ``` Optionally, many parsers allow adding syntax highlighting by specifying the code's language immediately after the firs...

INSERT INTO Customers (FName, LName, PhoneNumber) SELECT FName, LName, PhoneNumber FROM Employees This example will insert all Employees into the Customers table. Since the two tables have different fields and you don't want to move all the fields over, you need to set which fields to insert int...

The "default" for constructors is that they do not have any arguments. In case you do not specify any constructor, the compiler will generate a default constructor for you. This means the following two snippets are semantically equivalent: public class TestClass { private String tes...

HTML input validation is done automatically by the browser based on special attributes on the input element. It could partially or completely replace JavaScript input validation. This kind of validation can be circumvented by the user via specially crafted HTTP requests, so it does not replace serve...

Reflection is often used as part of software testing, such as for the runtime creation/instantiation of mock objects. It's also great for inspecting the state of an object at any given point in time. Here's an example of using Reflection in a unit test to verify a protected class member contains the...

The first two arguments to format are an output stream and a control string. Basic use does not require additional arguments. Passing t as the stream writes to *standard-output*. > (format t "Basic Message") Basic Message nil That expression will write Basic Message to standard ou...

docker run -p "8080:8080" myApp docker run -p "192.168.1.12:80:80" nginx docker run -P myApp In order to use ports on the host have been exposed in an image (via the EXPOSE Dockerfile directive, or --expose command line option for docker run), those ports need to be bound to...

main = do input <- getContents putStr input Input: This is an example sentence. And this one is, too! Output: This is an example sentence. And this one is, too! Note: This program will actually print parts of the output before all of the input has been fully read in. This m...

main = do line <- getLine putStrLn line Input: This is an example. Output: This is an example.

readFloat :: IO Float readFloat = fmap read getLine main :: IO () main = do putStr "Type the first number: " first <- readFloat putStr "Type the second number: " second <- readFloat putStrLn $ show first ++ " + " ++ show se...

Like in several other parts of the I/O library, functions that implicitly use a standard stream have a counterpart in System.IO that performs the same job, but with an extra parameter at the left, of type Handle, that represents the stream being handled. For instance, getLine :: IO String has a cou...

A bit counter-intuitive to the way most other languages' standard I/O libraries do it, Haskell's isEOF does not require you to perform a read operation before checking for an EOF condition; the runtime will do it for you. import System.IO( isEOF ) eofTest :: Int -> IO () eofTest line = do ...

During a merge, you can pass --ours or --theirs to git checkout to take all changes for a file from one side or the other of a merge. $ git checkout --ours -- file1.txt # Use our version of file1, delete all their changes $ git checkout --theirs -- file2.txt # Use their version of file2, delete ...

To stop a running container: docker stop <container> [<container>...] This will send the main process in the container a SIGTERM, followed by a SIGKILL if it doesn't stop within the grace period. The name of each container is printed as it stops. To start a container which is stoppe...

Ordinarily, images are pulled automatically from Docker Hub. Docker will attempt to pull any image from Docker Hub that doesn't already exist on the Docker host. For example, using docker run ubuntu when the ubuntu image is not already on the Docker host will cause Docker to initiate a pull of the l...

$ docker images REPOSITORY TAG IMAGE ID CREATED SIZE hello-world latest 693bce725149 6 days ago 967 B postgres 9.5 0f3af79d8673 10 weeks ago 265.7 MB postgres ...

Once you've paused execution on a breakpoint, you may want to follow execution line-by-line to observe what happens. Open your browser's Developer Tools and look for the Execution Control icons. (This example uses the icons in Google Chrome, but they'll be similar in other browsers.) Resume: Unpau...

Razor has its own comment syntax which begins with @* and ends with *@. Inline Comment: <h1>Comments can be @*hi!*@ inline</h1> Multi-line Comment: @* Comments can spread over multiple lines *@ HTML Comment You can also use the normal HTML comment syntax starting with &...

While inside a Razor code block, the browser will only recognize HTML code if the code is escaped. Use @: for a Single line: @foreach(int number in Model.Numbers) { @:<h1>Hello, I am a header!</h1> } Use <text> ... </text> for Multi-line: @{ var number = 1; ...