Tutorial by Examples: g

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(...

The ng-required adds or removes the required validation attribute on an element, which in turn will enable and disable the require validation key for the input. It is used to optionally define if an input element is required to have a non-empty value. The directive is helpful when designing validat...

// 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; } ...

Unfortunately as of C++14 there's no dynamic size matrix class in the C++ standard library. Matrix classes that support dynamic size are however available from a number of 3rd party libraries, including the Boost Matrix library (a sub-library within the Boost library). If you don't want a dependenc...

Because in .NET 3.5 and older you don't have Lazy<T> class you use the following pattern: public class Singleton { private Singleton() // prevents public instantiation { } public static Singleton Instance { get { return Nested.instanc...

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...

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 ...

You will often need to access instances of classes from the framework itself (like the WSClient, or the Configuration). You can inject them in your own classes : class ComplexService @Inject()( configuration: Configuration, wsClient: WSClient, applicationLifecycle: ApplicationLifecycle, ...

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; //...

CanCan is a a popular authorization library for Ruby on Rails which restricts user access to specific resources. The latest gem (CanCanCan) is a continuation of the dead project CanCan. Permissions are defined in the Ability class and can be used from controllers, views, helpers, or any other place...

Abilities are defined in the Ability class using can and cannot methods. Consider the following commented example for basic reference: class Ability include CanCan::Ability def initialize(user) # for any visitor or user can :read, Article if user if user.admin? ...

Once the number of abilities definitions start to grow in number, it becomes more and more difficult to handle the Ability file. The first strategy to handle these issue is to move abilities into meaningful methods, as per this example: class Ability include CanCan::Ability def initialize(...

Step 1: Create the controller, set the delegate, and conform to the protocol //Swift class ImageUploadViewController: UIViewController, UIImagePickerControllerDelegate, UINavigationControllerDelegate { let imagePickerController = UIImagePickerController() override func viewDi...

LISP and Scheme's greatest advantage over other mainstream programming language is their macro system. Unlike the C preprocessor and other macro languages, Scheme macros take parsed code as input and return expanded code as output. This is one of the applications of Scheme's “code is data” phrase, a...

When you implement java.io.Serializable interface to make a class serializable, the compiler looks for a static final field named serialVersionUID of type long. If the class doesn't have this field declared explicitly then the compiler will create one such field and assign it with a value which come...

Download the Atlassian conversion utility here. This utility requires Java, so please ensure that you have the Java Runtime Environment JRE installed on the machine you plan to do the conversion. Use the command java -jar svn-migration-scripts.jar verify to check if your machine is missing any of t...