Tutorial by Examples: d

// Example of raw dynamic size array. It's generally better to use std::vector. #include <algorithm> // std::sort #include <iostream> using namespace std; auto int_from( istream& in ) -> int { int x; in >> x; return x; } auto main() -> int { ...

// 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; } ...

// A fixed size raw array matrix (that is, a 2D raw array). #include <iostream> #include <iomanip> using namespace std; auto main() -> int { int const n_rows = 3; int const n_cols = 7; int const m[n_rows][n_cols] = // A raw array matrix. ...

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...

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(...

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...

Converting an integer type to the corresponding promoted type is better than converting it to some other integer type. void f(int x); void f(short x); signed char c = 42; f(c); // calls f(int); promotion to int is better than conversion to short short s = 42; f(s); // calls f(short); exact mat...

A file can be opened for reading as a stream using WITH-OPEN-FILE macro. (with-open-file (file #P"test.file") (loop for i from 0 for line = (read-line file nil nil) while line do (format t "~d: ~a~%" i line))) ; 0: Foobar ; 1: Barfoo ; 2: Quuxbar...

Method stopLoading() stops the current loading process of the webview. Swift webview.stopLoading() Objective-C [webview stopLoading];

Swift webview.reload() Objective-C [webview reload];

Whatever you do to customize Vim, it should NEVER happen outside of $HOME: on Linux, BSD and Cygwin, $HOME is usually /home/username/, on Mac OS X, $HOME is /Users/username/, on Windows, $HOME is usually C:\Users\username\. The canonical location for your vimrc and your vim directory is at ...

Don't forget the bang to allow Vim to overwrite that command next time you reload your vimrc. Custom commands must start with an uppercase character. Examples command! MyCommand call SomeFunction() command! MyOtherCommand command | Command | command See :help user-commands.

Autocommand groups are good for organization but they can be useful for debugging too. Think of them as small namespaces that you can enable/disable at will. Example augroup MyGroup " Clear the autocmds of the current group to prevent them from piling " up each time you rel...

if v:version >= 704 " Do something if Vim is the right version. endif if has('patch666') " Do something if Vim has the right patch-level. endif if has('feature') " Do something if Vim is built with 'feature'. endif See :help has-patch and :help feature-li...