Tutorial by Examples: const

Constructing collections from existing data

Standard Collections Java Collections framework A simple way to construct a List from individual data values is to use java.utils.Arrays method Arrays.asList: List<String> data = Arrays.asList("ab", "bc", "cd", "ab", "bc", "cd"); ...

Java Language • Collections

Constructor Injection

Constructor injection is the safest way of injecting dependencies that a whole class depends upon. Such dependencies are often referred to as invariants, since an instance of the class cannot be created without supplying them. By requiring the dependency to be injected at construction, it is guara...

unit-testing • Dependency Injection

Showcasing all common Angular constructs

The following example shows common AngularJS constructs in one file: <!DOCTYPE html> <html ng-app="myDemoApp"> <head> <style>.started { background: gold; }</style> <script src="https://code.angularjs.org/1.5.8/angular.min.js">&lt...

AngularJS • Getting started with AngularJS

Conversion to (const) char*

In order to get const char* access to the data of a std::string you can use the string's c_str() member function. Keep in mind that the pointer is only valid as long as the std::string object is within scope and remains unchanged, that means that only const methods may be called on the object. C++1...

C++ • std::string

Default Constructor

The "default" for constructors is that they do not have any arguments. In case you do not specify any constructor, the compiler will generate a default constructor for you. This means the following two snippets are semantically equivalent: public class TestClass { private String tes...

Java Language • Constructors

Constructor with Arguments

Constructors can be created with any kinds of arguments. public class TestClass { private String testData; public TestClass(String testData) { this.testData = testData; } } Called like this: TestClass testClass = new TestClass("Test Data"); A class can ...

Java Language • Constructors

Parsing and constructing an object from standard input

readFloat :: IO Float readFloat = fmap read getLine main :: IO () main = do putStr "Type the first number: " first <- readFloat putStr "Type the second number: " second <- readFloat putStrLn $ show first ++ " + " ++ show se...

Haskell Language • IO

Usage with non-default constructors

You can combine object initializers with constructors to initialize types if necessary. Take for example a class defined as such: public class Book { public string Title { get; set; } public string Author { get; set; } public Book(int id) { //do things } // the...

C# Language • Object initializers

Constraining Generic Placeholder Types

It is possible to force the type parameters of a generic class to implement a protocol, for example, Equatable class MyGenericClass<Type: Equatable>{ var value: Type init(value: Type){ self.value = value } func getValue() -> Type{ return self....

Swift Language • Generics

Setting constraints programmatically

Boilerplate code example override func viewDidLoad() { super.viewDidLoad() let myView = UIView() myView.backgroundColor = UIColor.blueColor() myView.translatesAutoresizingMaskIntoConstraints = false view.addSubview(myView) // Add constraints code here // ... ...

iOS • Auto Layout

Center Constraints

Select your button (or whatever view you want to center) on the storyboard. Then click the align button on the bottom right. Select Horizontally in Container and Vertically in Container. Click "Add 2 Constraints". If it wasn't perfectly centered already, you may need to do one more thin...

iOS • Auto Layout

Constants (Const)

If you have a value that never changes in your application, you can define a named constant and use it in place of a literal value. You can use Const only at module or procedure level. This means the declaration context for a variable must be a class, structure, module, procedure, or block, and can...

VBA • Declaring Variables

Inheritance. Constructors' calls sequence

Consider we have a class Animal which has a child class Dog class Animal { public Animal() { Console.WriteLine("In Animal's constructor"); } } class Dog : Animal { public Dog() { Console.WriteLine("In Dog's constructor"); } ...

C# Language • Inheritance

Constants

math modules includes two commonly used mathematical constants. math.pi - The mathematical constant pi math.e - The mathematical constant e (base of natural logarithm) >>> from math import pi, e >>> pi 3.141592653589793 >>> e 2.718281828459045 >>> P...

Python Language • Math Module

Forcing a static constructor to be called

While static constructors are always called before the first usage of a type it's sometimes useful to be able to force them to be called and the RuntimeHelpers class provide an helper for it: using System.Runtime.CompilerServices; // ... RuntimeHelpers.RunClassConstructor(typeof(Foo).TypeHand...

C# Language • Constructors and Finalizers

Drop Constraint

ALTER TABLE Employees DROP CONSTRAINT DefaultSalary This Drops a constraint called DefaultSalary from the employees table definition. Note:- Ensure that constraints of the column are dropped before dropping a column.

SQL • ALTER TABLE

Add Constraint

ALTER TABLE Employees ADD CONSTRAINT DefaultSalary DEFAULT ((100)) FOR [Salary] This adds a constraint called DefaultSalary which specifies a default of 100 for the Salary column. A constraint can be added at the table level. Types of constraints Primary Key - prevents a duplicate record in...

SQL • ALTER TABLE

Construct a string from Array

The String.Join method will help us to construct a string From array/list of characters or string. This method accepts two parameters. The first one is the delimiter or the separator which will help you to separate each element in the array. And the second parameter is the Array itself. String from...

C# Language • Common String Operations

Declaring a constant

Constants are declared like variables, but using the const keyword: const Greeting string = "Hello World" const Years int = 10 const Truth bool = true Like for variables, names starting with an upper case letter are exported (public), names starting with lower case are not. // not e...

Go • Constants

Listing available constructors for a class

5.0 In PowerShell 5.0+ you can list available constructors by calling the static new-method without parentheses. PS> [DateTime]::new OverloadDefinitions ------------------- datetime new(long ticks) datetime new(long ticks, System.DateTimeKind kind) datetime new(int year, int month, int d...

PowerShell • PowerShell Classes