Tutorial by Examples: en

The Java language allows you to use new to create instances Integer, Boolean and so on, but it is generally a bad idea. It is better to either use autoboxing (Java 5 and later) or the valueOf method. Integer i1 = new Integer(1); // BAD Integer i2 = 2; // BEST (autoboxing)...

Using new String(String) to duplicate a string is inefficient and almost always unnecessary. String objects are immutable, so there is no need to copy them to protect against changes. In some older versions of Java, String objects can share backing arrays with other String objects. In those ver...

A statement is constructed with a function such as sqlite3_prepare_v2(). A prepared statement object must be cleaned up with sqlite3_finalize(). Do not forget this in case of an error. If parameters are used, set their values with the sqlite3_bind_xxx() functions. The actual execution happens whe...

An enumerations value in no way needs to be unique: #include <stdlib.h> /* for EXIT_SUCCESS */ #include <stdio.h> /* for printf() */ enum Dupes { Base, /* Takes 0 */ One, /* Takes Base + 1 */ Two, /* Takes One + 1 */ Negative = -1, AnotherZero /* Takes Negativ...

CROSS APPLY enables you to "join" rows from a table with dynamically generated rows returned by some table-value function. Imagine that you have a Company table with a column that contains an array of products (ProductList column), and a function that parse these values and returns a set ...

It is well known that you cannot use the same file for input and ouput in the same command. For instance, $ cat header.txt body.txt >body.txt doesn’t do what you want. By the time cat reads body.txt, it has already been truncated by the redirection and it is empty. The final result will be th...

ORDER BY x ASC -- same as default ORDER BY x DESC -- highest to lowest ORDER BY lastname, firstname -- typical name sorting; using two columns ORDER BY submit_date DESC -- latest first ORDER BY submit_date DESC, id ASC -- latest first, but fully specifying order. ASC = ASCENDING, DESC ...

When the shell performs parameter expansion, command substitution, variable or arithmetic expansion, it scans for word boundaries in the result. If any word boundary is found, then the result is split into multiple words at that position. The word boundary is defined by a shell variable IFS (Interna...

A simple example which provides the options: OptAlt. OptDetails-h--helpShow help-v--versionShow version info-dr path--doc-root pathAn option which takes a secondary parameter (a path)-i--installA boolean option (true/false)-*--Invalid option #!/bin/bash dr='' install=false skip=false for op ...

The following function reads an entire file into a new string and returns it: (defun read-file (infile) (with-open-file (instream infile :direction :input :if-does-not-exist nil) (when instream (let ((string (make-string (file-length instream)))) (read-sequence string instr...

SET TEST=0 IF %TEST% == 0 ( echo TEST FAILED ) ELSE IF %TEST% == 1 ( echo TEST PASSED ) ELSE ( echo TEST INVALID )

Basic Syntax Julia's array comprehensions use the following syntax: [expression for element = iterable] Note that as with for loops, all of =, in, and ∈ are accepted for the comprehension. This is roughly equivalent to creating an empty array and using a for loop to push! items to it. result ...

Enumeration types can also be declared without giving them a name: enum { buffersize = 256, }; static unsigned char buffer [buffersize] = { 0 }; This enables us to define compile time constants of type int that can as in this example be used as array length.

static void setupQualityHigh(Graphics2D g2d) { g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON); g2d.setRenderingHint(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY); // many other RenderingHints KEY/VALUE pairs to specify } ...

String types like UnicodeString, AnsiString, WideString and UTF8String are stored in a memory using their respective encoding (see String Types for more details). Assigning one type of string into another may result in a conversion. Type string is designed to be encoding independent - you should nev...

Steps#1-5 below allow any image or path-shape to be both moved anywhere on the canvas and rotated to any angle without changing any of the image/path-shape's original point coordinates. Move the canvas [0,0] origin to the shape's center point context.translate( shapeCenterX, shapeCenterY ); ...

You can improve the security for data transit or storing by implementing encrypting techniques. Basically there are two approaches when using System.Security.Cryptography: symmetric and asymmetric. Symmetric Encryption This method uses a private key in order to perform the data transformation. ...

One of the core benefits of Typescript is that it enforces data types of values that you are passing around your code to help prevent mistakes. Let's say you're making a pet dating application. You have this simple function that checks if two pets are compatible with each other... checkCompatible...

This very simple snippet of XQuery can be executed in QueryConsole using the built-in "Documents" database as a sandbox. Each piece of the snippet has a comment to explain what the following line of code means. xquery version "1.0-ml"; (: Let's first insert a simple document to...

If we know the desired URI of the document we are looking for: fn:doc("/stuff/mysimpledocument.xml") Returns the full document from the database, using the URI to locate it. Since this is XQuery, we can use XPath to find the document when we know about the structure, but not the URI: ...