Tutorial by Examples: b

If your application is available in different languages, you usually show the current locale in the URL. scope '/(:locale)', locale: /#{I18n.available_locales.join('|')}/ do root 'example#root' # other routes end Your root will be accessible via the locales defined in I18n.available_l...

From Apple documentation: Use the CTCallCenter class to obtain a list of current cellular calls, and to respond to state changes for calls such as from a dialing state to a connected state. Such state changes are known as cellular call events. The purpose of CTCallCenter is to give the develop...

You can subclass SKSpriteNode and define your own type of sprite. class Hero: SKSpriteNode { //Use a convenience init when you want to hard code values convenience init() { let texture = SKTexture(imageNamed: "Hero") self.init(texture: texture, color: .clearCol...

In contrast to segue that lets you pass data "forward" from current view controller to destination view controller: (VC1) -> (VC2) Using "unwind" you can do the opposite, pass data from the destination or current view controller to its presenting view controller: (VC1) <...

There are cases, where custom objects need to be created and defined in the resources of the application. Such objects can be composed of Java simple types, for example Integer, Float, String. Here is the example of how to import an object defined in application resources. The object Category cons...

RoboGuice is a framework that brings the simplicity and ease of Dependency Injection to Android, using Google's own Guice library. RoboGuice 3 slims down your application code. Less code means fewer opportunities for bugs. It also makes your code easier to follow -- no longer is your code littered ...

It's possible to break / continue to an outer loop by using label statements: outerloop: for(...) { innerloop: for(...) { if(condition1) break outerloop; if(condition2) continue innerloop; // equivalent to: continue; } } There is no ...

If you want the Value Types vs Reference Types in methods example to work properly, use the ref keyword in your method signature for the parameter you want to pass by reference, as well as when you call the method. public static void Main(string[] args) { ... DoubleNumber(ref number); ...

C-style bit manipulation A bit can be set using the bitwise OR operator (|). // Bit x will be set number |= 1LL << x; Using std::bitset set(x) or set(x,true) - sets bit at position x to 1. std::bitset<5> num(std::string("01100")); num.set(0); // num is now 01101 ...

C-style bit-manipulation A bit can be cleared using the bitwise AND operator (&). // Bit x will be cleared number &= ~(1LL << x); Using std::bitset reset(x) or set(x,false) - clears the bit at position x. std::bitset<5> num(std::string("01100")); num.reset(2); ...

C-style bit-manipulation A bit can be toggled using the XOR operator (^). // Bit x will be the opposite value of what it is currently number ^= 1LL << x; Using std::bitset std::bitset<4> num(std::string("0100")); num.flip(2); // num is now 0000 num.flip(0); // num is n...

C-style bit-manipulation The value of the bit can be obtained by shifting the number to the right x times and then performing bitwise AND (&) on it: (number >> x) & 1LL; // 1 if the 'x'th bit of 'number' is set, 0 otherwise The right-shift operation may be implemented as either a...

C-style bit-manipulation // Bit n will be set if x is 1 and cleared if x is 0. number ^= (-x ^ number) & (1LL << n); Using std::bitset set(n,val) - sets bit n to the value val. std::bitset<5> num(std::string("00100")); num.set(0,true); // num is now 00101 num.set(...

// Example of std::vector as an expanding dynamic size array. #include <algorithm> // std::sort #include <iostream> #include <vector> // std::vector using namespace std; int int_from( std::istream& in ) { int x = 0; in >> x; return x; } ...

This is useful to see if there are any non-printable characters, or non-ASCII characters. e.g. If you have copy-pasted the code from web, you may have quotes like ” instead of standard ". $ cat -v file.txt $ cat -vE file.txt # Useful in detecting trailing spaces. e.g. $ echo '” ' | c...

To create a new Rails 5 API, open a terminal and run the following command: rails new app_name --api The following file structure will be created: create create README.rdoc create Rakefile create config.ru create .gitignore create Gemfile create app create app/as...

RVM is a great tool to manage your ruby versions and set up your working environment. Assuming you already have RVM installed, to get the latest version of ruby, which is needed for these examples, open a terminal and run: $ rvm get stable $ rvm install ruby --latest Check your ruby version by...

A typical singleton class : import javax.inject._ @Singleton class BurgersRepository { // implementation goes here } Another class, requiring access to the first one. import javax.inject._ class FastFoodService @Inject() (burgersRepository: BurgersRepository){ // implementation ...

Basic usage of dependency injection is done by the annotations. When you need to tweak things a little bit, you need custom code to further specify how you want some classes to be instantiated and injected. This code goes in what is called a Module. import com.google.inject.AbstractModule // Pla...

PBKDF2 ("Password-Based Key Derivation Function 2") is one of the recommended hash-functions for password-hashing. It is part of rfc-2898. .NET's Rfc2898DeriveBytes-Class is based upon HMACSHA1. using System.Security.Cryptography; ... public const int SALT_SIZE = 24; //...