Tutorial by Examples: const

A typeglob *foo holds references to the contents of global variables with that name: $foo, @foo, $foo, &foo, etc. You can access it like an hash and assign to manipulate the symbol tables directly (evil!). use v5.10; # necessary for say our $foo = "foo"; our $bar; say ref *foo{SCAL...

A constructor is a special method in a class that is called when an instance of an object is created. It is a regular MATLAB function that accepts input parameters but it also must follow certain rules. Constructors are not required as MATLAB creates a default one. In practice, however, this is a p...

Objects come in their own class, so a simple example would be a car (detailed explanations below): public class Car { //Variables describing the characteristics of an individual car, varies per object private int milesPerGallon; private String name; private String color; ...

/** * @param num Numerator * @param denom Denominator * @throws ArithmeticException in case `denom` is `0` */ class Division @throws[ArithmeticException](/*no annotation parameters*/) protected (num: Int, denom: Int) { private[this] val wrongValue = num / denom /** Integer n...

A const Enum is the same as a normal Enum. Except that no Object is generated at compile time. Instead, the literal values are substituted where the const Enum is used. // Typescript: A const Enum can be defined like a normal Enum (with start value, specifig values, etc.) const enum NinjaActivity ...

A default constructor is a type of constructor that requires no parameters when called. It is named after the type it constructs and is a member function of it (as all constructors are). class C{ int i; public: // the default constructor definition C() : i(0){ // member initial...

To work with ConstraintLayout, you need Android Studio Version 2.2 or newer and have at least version 32 (or higher) of Android Support Repository. Add the Constraint Layout library as a dependency in your build.gradle file: dependencies { compile 'com.android.support.constraint:constraint...

Passing a pointer argument to a T* parameter, if possible, is better than passing it to a const T* parameter. struct Base {}; struct Derived : Base {}; void f(Base* pb); void f(const Base* pb); void f(const Derived* pd); void f(bool b); Base b; f(&b); // f(Base*) is better than f(const...

int main (void) { const int foo_readonly = 10; int *foo_ptr; foo_ptr = (int *)&foo_readonly; /* (1) This casts away the const qualifier */ *foo_ptr = 20; /* This is undefined behavior */ return 0; } Quoting ISO/IEC 9899:201x, section 6.7.3 §2: If an attempt i...

A variable declared constexpr is implicitly const and its value may be used as a constant expression. Comparison with #define A constexpr is type-safe replacement for #define based compile-time expressions. With constexpr the compile-time evaluated expression is replaced with the result. For examp...

' Making a factory with parameter to the class Public Function new_Car(wheels) Set new_Car = New Car new_Car.Wheels = wheels End Function ' Creating a car through a factory Dim semiTrailer Set semiTrailer = new_Car(18)

angular .module('MyApp', []) .constant('VERSION', 1.0); Your constant is now declared and can be injected in a controller, a service, a factory, a provider, and even in a config method: angular .module('MyApp') .controller('FooterController', function(VERSION) { this.version = V...

Here are examples of how to use monotonic predicates instead of impure, non-monotonic constructs in your programs: dif/2 is meant to be used instead of non-monotonic constructs like (\=)/2 arithmetic constraints (CLP(FD), CLP(Q) and others) are meant to be used instead of moded arithmetic predi...

(This is a request for a good example that shows how to construct a SELECT using CONCAT, then prepare+execute it. Please emphasize the use of @variables versus DECLAREd variables -- it makes a big difference, and it is something that novices (include myself) stumble over.)

Value constructors are functions that return a value of a data type. Because of this, just like any other function, they can take one or more parameters: data Foo = Bar String Int | Biz String Let's check the type of the Bar value constructor. :t Bar prints Bar :: String -> Int -> Foo...

This error occurs when tables are not adequately structured to handle the speedy lookup verification of Foreign Key (FK) requirements that the developer is mandating. CREATE TABLE `gtType` ( `type` char(2) NOT NULL, `description` varchar(1000) NOT NULL, PRIMARY KEY (`type`) ) ENGINE=InnoD...

In D we can use constructors to initialize structs just like a class. To define a construct for the struct declared in the previous example we can type: struct Person { this(int age, int height) { this.age = age; this.height = height; this.ageXHeight = cast(float)age...

MY_CONSTANT = "Hello, world" # constant Constant = 'This is also constant' # constant my_variable = "Hello, venus" # not constatn Constant name start with capital letter. Everything that start with capital letter are considered as constant in Ruby. So class and module are al...

MY_CONSTANT = "Hello, world" MY_CONSTANT = "Hullo, world" The above code results in a warning, because you should be using variables if you want to change their values. However it is possible to change one letter at a time in a constant without a warning, like this: MY_CONST...

def say_hi MESSAGE = "Hello" puts MESSAGE end The above code results in an error: SyntaxError: (irb):2: dynamic constant assignment.