Tutorial by Examples: b

If you need to clean the build: ndk-build clean

Reflection is useful but fragile. Consider this: let mi = typeof<System.String>.GetMethod "StartsWith" The problems with this kind of code are: The code doesn't work because there are several overloads of String.StartsWith Even if there wouldn't be any overloads right now la...

Create a DATABASE. Note that the shortened word SCHEMA can be used as a synonym. CREATE DATABASE Baseball; -- creates a database named Baseball If the database already exists, Error 1007 is returned. To get around this error, try: CREATE DATABASE IF NOT EXISTS Baseball; Similarly, DROP DATA...

A lambda closure is created when a lambda expression references the variables of an enclosing scope (global or local). The rules for doing this are the same as those for inline methods and anonymous classes. Local variables from an enclosing scope that are used within a lambda have to be final. Wit...

All constructors in Java must make a call to the Object constructor. This is done with the call super(). This has to be the first line in a constructor. The reason for this is so that the object can actually be created on the heap before any additional initialization is performed. If you do not spe...

To improve performance one might want to add indexes to columns ALTER TABLE TABLE_NAME ADD INDEX `index_name` (`column_name`) altering to add composite (multiple column) indexes ALTER TABLE TABLE_NAME ADD INDEX `index_name` (`col1`,`col2`)

The normal way to create an array of numbers: numbers = [1, 2, 3, 4, 5] Range objects can be used extensively to create an array of numbers: numbers = Array(1..10) # => [1, 2, 3, 4, 5, 6, 7, 8, 9, 10] numbers = (1..10).to_a # => [1, 2, 3, 4, 5, 6, 7, 8, 9, 10] #step and #map methods...

These are the bitwise operators in VB.NET : And, Or, Xor, Not Example of And bitwise operation Dim a as Integer a = 3 And 5 The value of a will be 1. The result is obtained after comparing 3 and 5 in binary for. 3 in binary form is 011 and 5 in binary form is 101. The And operator places 1 if ...

using System; using System.Threading; using System.Threading.Tasks; class Program { static void Main( string[] args ) { object sync = new object(); int sum = 0; Parallel.For( 1, 1000, ( i ) => { lock( sync ) sum = sum + i; // lock is necessa...

Not all objects can be converted to a JSON string. When an object has cyclic self-references, the conversion will fail. This is typically the case for hierarchical data structures where parent and child both reference each other: const world = { name: 'World', regions: [] }; world.region...

abstract class Machine { constructor(public manufacturer: string) { } // An abstract class can define methods of it's own, or... summary(): string { return `${this.manufacturer} makes this machine.`; } // Require inheriting classes to implement methods ...

Create a MongoDB connection, that later you can query: $manager = new \MongoDB\Driver\Manager('mongodb://localhost:27017'); In the next example, you will learn how to query the connection object. This extension close the connection automatically, it's not necessary to close manually.

Using range-base loops, you can loop over a sub-part of a given container or other range by generating a proxy object that qualifies for range-based for loops. template<class Iterator, class Sentinel=Iterator> struct range_t { Iterator b; Sentinel e; Iterator begin() const { return ...

Using the Employees Table, below is an example to return the Id, FName and LName columns in (ascending) LName order: SELECT Id, FName, LName FROM Employees ORDER BY LName Returns: IdFNameLName2JohnJohnson1JamesSmith4JohnathonSmith3MichaelWilliams To sort in descending order add the DESC keywo...

Multiple fields can be specified for the ORDER BY clause, in either ASCending or DESCending order. For example, using the http://stackoverflow.com/documentation/sql/280/example-databases/1207/item-sales-table#t=201607211314066434211 table, we can return a query that sorts by SaleDate in ascending o...

ARC can be disabled for individual files by adding the -fno-objc-arc compiler flag for each file. Conversely it can be added in Targets ▸ Build Phases ▸ Compile Sources

Prolog categorizes everything into: Atoms - Any sequence of characters that do not start with an uppercase alphabet. Eg - a, b, okay Numbers - There is no special syntax for numbers, no declaration is required. Eg 1, 22, 35.8 Variables - A string which starts with an uppercase character or unde...

Usually grep prints only matching lines. In the example below seq 9 generates a list of numbers from 1 to 9, one per line, and grep prints a single matching line: seq 9 | grep 5 # 5 The -C n option (or --context=n in long form) prints n lines before and after each matching line, in addition to ...

In this example, a private static instance of the class is declared at its beginning. The value of a static field is shared between instances, so if a new instance of this class gets created the if will find a reference to the first Singleton object, destroying the new instance (or its game object)...

import std.stdio; bool isPrime(int number) { foreach(i; 2..number) { if (number % i == 0) { return false; } } return true; } void main() { writeln(2.isPrime); writeln(3.isPrime); writeln(4.isPrime); 5.isPrime.writeln; } ...