Tutorial by Examples: an

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; } ...

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...

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(...

mount is used to mount another application (basically rack application) or rails engines to be used within the current application syntax: mount SomeRackApp, at: "some_route" Now you can access above mounted application using route helper some_rack_app_path or some_rack_app_url. But ...

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...

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...

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...

The angular.equals function compares and determines if 2 objects or values are equal, angular.equals performs a deep comparison and returns true if and only if at least 1 of the following conditions is met. angular.equals(value1, value2) If the objects or values pass the === comparison If b...

The function angular.isString returns true if the object or value given to it is of the type string angular.isString(value1) Examples angular.isString("hello") // true angular.isString([1, 2]) // false angular.isString(42) // false This is the equivalent of performing typeof s...

The angular.isArray function returns true if and only if the object or value passed to it is of the type Array. angular.isArray(value) Examples angular.isArray([]) // true angular.isArray([2, 3]) // true angular.isArray({}) // false angular.isArray(17) // false It is the equivalent of ...

Using the baseline-shift parameter, you can specify super- or subscript. But this is not supported by all major browsers. <svg xmlns="http://www.w3.org/2000/svg"> <text x="10" y="20">x<tspan baseline-shift="super">2</tspan></te...

Example for date or time range.

The aar file doesn't contain the transitive dependencies and doesn't have a pom file which describes the dependencies used by the library. It means that, if you are importing a aar file using a flatDir repo you have to specify the dependencies also in your project. You should use a maven repositor...

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

Object obj = new Object(); // Note the 'new' keyword Where: Object is a reference type. obj is the variable in which to store the new reference. Object() is the call to a constructor of Object. What happens: Space in memory is allocated for the object. The constructor Object() is call...