Tutorial by Examples: w

// 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. ...

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...

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...

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...

Will select records in TableName that have records matching in TableName1. SELECT * FROM TableName t WHERE EXISTS ( SELECT 1 FROM TableName1 t1 where t.Id = t1.Id)

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...

The macro WITH-OUTPUT-TO-STRING can be used to create a string output stream, and return the resulting string at the end. (with-output-to-string (str) (write-line "Foobar!" str) (write-string "Barfoo!" str)) ;=> "Foobar! ; Barfoo!" The same can be done ...

A file can be opened for writing as a stream using WITH-OPEN-FILE macro. (with-open-file (file #P"test.file" :direction :output :if-exists :append :if-does-not-exist :create) (dolist (line '("Foobar" &q...

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

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

git show shows various Git objects. For commits: Shows the commit message and a diff of the changes introduced. CommandDescriptiongit showshows the previous commitgit show @~3shows the 3rd-from-last commit For trees and blobs: Shows the tree or blob. CommandDescriptiongit show @~3:shows the ...

In case we want to use enum with more information and not just as constant values, and we want to be able to compare two enums. Consider the following example: public enum Coin { PENNY(1), NICKEL(5), DIME(10), QUARTER(25); private final int value; Coin(int value){ this....

<svg xmlns="http://www.w3.org/2000/svg"> <text x="40" y="60" font-size="28">Hello World!</text> </svg> The x and y coordinate specifies the position of the bottom-left corner of the text (unless text-anchor has been modified). ...

<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"> <line x1="10" y1="10" x2="100" y2="100" stroke="red" stroke-width="10" /> <line x1="100" y1="10&...

In a module (library or application) where you need the aar file you have to add in your build.gradle the repository: repositories { flatDir { dirs 'libs' } } and add the dependency: dependencies { compile(name:'nameOfYourAARFileWithoutExtension', ext:'aar') } Pay a...

The XMPP network can be thought of as a bidirected graph with servers (S) operating in a mesh, clients (C) clustered about their local server, and streams represented by extraverted edges: When a client wants to send data (eg. a message or presence information) across the network to another clien...

In some cases, you want to show your users a UIPickerView with predefined contents for a UITextField instead of a keyboard. Create a custom UIPickerView At first, you need a custom wrapper-class for UIPickerView conforming to the protocols UIPickerViewDataSource and UIPickerViewDelegate. class My...

NSString *someString = @" Objective-C Language \n"; NSString *trimmedString = [someString stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]]; //Output will be - "Objective-C Language" Method stringByTrimmingCharactersInSet returns a new str...

Data attributes were introduced in HTML5 which is supported by all modern browsers, but older browsers before HTML5 don't recognize the data attributes. However, in HTML specifications, attributes that are not recognized by the browser must be left alone and the browser will simply ignore them when...