Tutorial by Examples: ed

Typedef

Typedefs are declarations which have the keyword typedef in front and before the type. E.g.: typedef int (*(*t0)())[5]; (you can technically put the typedef after the type too - like this int typedef (*(*t0)())[5]; but this is discouraged) The above declarations declares an identifier for a typ...

C Language • Declarations

The default revision: HEAD

$ git show # equivalent to 'git show HEAD' 'HEAD' names the commit on which you based the changes in the working tree, and is usually the symbolic name for the current branch. Many (but not all) commands that take revision parameter defaults to 'HEAD' if it is missing.

Git • Git revisions syntax

Tracked / upstream branch: @{upstream}

$ git log @{upstream}.. # what was done locally and not yet published, current branch $ git show master@{upstream} # show upstream of branch 'master' The suffix @{upstream} appended to a branchname (short form <branchname>@{u}) refers to the branch that the branch specified by branc...

Git • Git revisions syntax

Reading a file using BufferedInputStream

Reading file using a BufferedInputStream generally faster than FileInputStream because it maintains an internal buffer to store bytes read from the underlying input stream. import java.io.BufferedInputStream; import java.io.FileInputStream; import java.io.IOException; public class FileReadin...

Java Language • File I/O

Generating Random Numbers with a Specified Seed

//Creates a Random instance with a seed of 12345. Random random = new Random(12345L); //Gets a ThreadLocalRandom instance ThreadLocalRandom tlr = ThreadLocalRandom.current(); //Set the instance's seed. tlr.setSeed(12345L); Using the same seed to generate random numbers will return the sa...

Java Language • Random Number Generation

How to edit jar files with ASM

Firstly the classes from the jar need to be loaded. We'll use three methods for this process: loadClasses(File) readJar(JarFile, JarEntry, Map) getNode(byte[]) Map<String, ClassNode> loadClasses(File jarFile) throws IOException { Map<String, ClassNode> classes = new HashMap&...

Java Language • Bytecode Modification

Try-finally nested inside try-except

A try-finally block may be nested inside a try-except block. try AcquireResources; try UseResource; finally ReleaseResource; end; except on E: EResourceUsageError do begin HandleResourceErrors; end; end; If an exception occurs inside UseResource, then execution...

Embarcadero Delphi • Use of try, except, and finally

Try-except nested inside try-finally

A try-except block may be nested inside a try-finally block. AcquireResource; try UseResource1; try UseResource2; except on E: EResourceUsageError do begin HandleResourceErrors; end; end; UseResource3; finally ReleaseResource; end; If an EResourceUsageE...

Embarcadero Delphi • Use of try, except, and finally

Clustered index

When using clustered index, the rows of the table are sorted by the column to which the clustered index is applied. Therefore, there can be only one clustered index on the table because you can't order the table by two different columns. Generally, it is best to use clustered index when performing ...

SQL • Indexes

Non clustered index

Nonclustered indexes are stored separately from the table. Each index in this structure contains a pointer to the row in the table which it represents. This pointers are called a row locators. The structure of the row locator depends on whether the data pages are stored in a heap or a clustered tab...

SQL • Indexes

Multiple producer/consumer example with shared global queue

Below code showcases multiple Producer/Consumer program. Both Producer and Consumer threads share same global queue. import java.util.concurrent.*; import java.util.Random; public class ProducerConsumerWithES { public static void main(String args[]) { BlockingQueue<Integer> ...

Java Language • Concurrent Programming (Threads)

GitHub Flavored Markdown

GitHub expands Markdown syntax to provide new useful features. Header # Header1 ## Header2 ### Header3 #### Header4 ##### Header5 ###### Header6 H1 === H2 --- Emphasis *Italic1* _Italic2_ **Bold1** __Bold2__ ***Bold_Italic*** ~~Strikethrough~~ Horizontal Line --- *** ___ ...

github • Getting started with github

Operator Precedence and Methods

From highest to lowest, this is the precedence table for Ruby. High precedence operations happen before low precedence operations. ╔═══════════════════════╦════════════════════════════════════════╦═════════╗ ║ Operators ║ Operations ║ Method? ║ ╠═══════════...

Ruby Language • Operators

Embedding into HTML

There are three possibilities to insert Elm code into a existing HTML page. Embed into the body tag Supposing you have compiled the Hello World example into elm.js file, you can let Elm take over the <body> tag like so: <!DOCTYPE html> <html> <body> <scri...

Elm Language • Getting started with Elm Language

Printing the Difference of the Values of two Pointers to an Object

Subtracting the values of two pointers to an object results in a signed integer *1. So it would be printed using at least the d conversion specifier. To make sure there is a type being wide enough to hold such a "pointer-difference", since C99 <stddef.h> defines the type ptrdiff_t. ...

C Language • Formatted Input/Output

Getting started and finding help

The package's official wiki has some essential materials: As a new user, you will want to check out the vignettes, FAQ and cheat sheet. Before asking a question -- here on StackOverflow or anywhere else -- please read the support page. For help on individual functions, the syntax is h...

data.table • Getting started with data.table

Prefer local variables to globals, attributes, and indexed values

Javascript engines first look for variables within the local scope before extending their search to larger scopes. If the variable is an indexed value in an array, or an attribute in an associative array, it will first look for the parent array before it finds the contents. This has implications wh...

JavaScript • Performance Tips

Editing index.ios.js or index.android.js

Open index.ios.js or index.android.js and delete everything between the <View> </View>. After that, write <Text> Hello World! </Text> and run the emulator. You should see Hello World! written on the screen! Congrats! You've successfully written your first Hello World!

react-native • Hello World

Editing values

# example data DT = as.data.table(mtcars, keep.rownames = TRUE) Editing a column Use the := operator inside j to create new columns or modify existing ones: DT[, mpg_sq := mpg^2] Editing on a subset of rows Use the i argument to subset to rows "where" edits should be made: DT[1:...

data.table • Adding and modifying columns

Installing on Fedora

Open a terminal and run: sudo dnf install arduino Open the Arduino application, or type arduino into the terminal

arduino • Arduino IDE