Default Constructor

	Default Constructor In computer programming languages, the term default constructor can refer to a constructor that is automatically generated by the compiler in the absence of any programmer-defined constructors (e.g. in Java), and is usually a nullary constructor. In other languages (e.g. in C++) it is a constructor that can be called without having to provide any arguments, irrespective of whether the constructor is auto-generated or user-defined. Note that a constructor with formal parameters can still be called without arguments if default arguments were provided in the constructor's definition. C++ In C++, the standard describes the default constructor for a class as a constructor that can be called with no arguments (this includes a constructor whose parameters all have default arguments). For example: class MyClass ; MyClass::MyClass() : x(100) // constructor defined int main() When allocating memory dynamically, the constructor may be called by adding parenthesis after the class na ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Nullary Constructor In computer programming, a nullary constructor is a constructor that takes no arguments. Also known as a 0-argument constructor, no-argument constructors or default constructor. Object-oriented constructors In object-oriented programming, a constructor is code that is run when an object is created. Default constructors of objects are usually nullary. Java example public class Example Algebraic data types In algebraic data types In computer programming, especially functional programming and type theory, an algebraic data type (ADT) is a kind of composite type, i.e., a type formed by combining other types. Two common classes of algebraic types are product types (i.e., ..., a constructor is one of many tags that wrap data. If a constructor does not take any data arguments, it is nullary. Haskell example -- nullary type constructor with two nullary data constructors data Bool = False , True -- non-nullary type constructor with one non-nullary data construc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
picture info	Programming Languages A programming language is a system of notation for writing computer programs. Most programming languages are text-based formal languages, but they may also be graphical. They are a kind of computer language. The description of a programming language is usually split into the two components of syntax (form) and semantics (meaning), which are usually defined by a formal language. Some languages are defined by a specification document (for example, the C programming language is specified by an ISO Standard) while other languages (such as Perl) have a dominant implementation that is treated as a reference. Some languages have both, with the basic language defined by a standard and extensions taken from the dominant implementation being common. Programming language theory is the subfield of computer science that studies the design, implementation, analysis, characterization, and classification of programming languages. Definitions There are many considerations when defining w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Constructor (computer Science) In class-based, object-oriented programming, a constructor (abbreviation: ctor) is a special type of subroutine called to create an object. It prepares the new object for use, often accepting arguments that the constructor uses to set required member variables. A constructor resembles an instance method, but it differs from a method in that it has no explicit return type, it is not implicitly inherited and it usually has different rules for scope modifiers. Constructors often have the same name as the declaring class. They have the task of initializing the object's data members and of establishing the invariant of the class, failing if the invariant is invalid. A properly written constructor leaves the resulting object in a ''valid'' state. Immutable objects must be initialized in a constructor. Most languages allow overloading the constructor in that there can be more than one constructor for a class, with differing parameters. Some languages take consideration of some s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Parameter (computer Science) In computer programming, a parameter or a formal argument is a special kind of variable used in a subroutine to refer to one of the pieces of data provided as input to the subroutine. These pieces of data are the values of the arguments (often called ''actual arguments'' or ''actual parameters'') with which the subroutine is going to be called/invoked. An ordered list of parameters is usually included in the definition of a subroutine, so that, each time the subroutine is called, its arguments for that call are evaluated, and the resulting values can be assigned to the corresponding parameters. Unlike ''argument'' in usual mathematical usage, the ''argument'' in computer science is the actual input expression passed/supplied to a function, procedure, or routine in the invocation/call statement, whereas the ''parameter'' is the variable inside the implementation of the subroutine. For example, if one defines the add subroutine as def add(x, y): return x + y, then x, y are paramet ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Default Argument In computer programming, a default argument is an argument to a function that a programmer is not required to specify. In most programming languages, functions may take one or more arguments. Usually, each argument must be specified in full (this is the case in the C programming language). Later languages (for example, in C++) allow the programmer to specify default arguments that always have a value, even if one is not specified when calling the function. Default arguments in C++ Consider the following function declaration: int MyFunc(int a, int b, int c = 12); This function takes three arguments, of which the last one has a default of twelve. The programmer may call this function in two ways: int result = MyFunc(1, 2, 3); result = MyFunc(1, 2); In the first case the value for the argument called ''c'' is specified as normal. In the second case, the argument is omitted, and the default value of ''12'' will be used instead. There is no means to know if the argument has ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
picture info	Java (programming Language) Java is a high-level, class-based, object-oriented programming language that is designed to have as few implementation dependencies as possible. It is a general-purpose programming language intended to let programmers ''write once, run anywhere'' ( WORA), meaning that compiled Java code can run on all platforms that support Java without the need to recompile. Java applications are typically compiled to bytecode that can run on any Java virtual machine (JVM) regardless of the underlying computer architecture. The syntax of Java is similar to C and C++, but has fewer low-level facilities than either of them. The Java runtime provides dynamic capabilities (such as reflection and runtime code modification) that are typically not available in traditional compiled languages. , Java was one of the most popular programming languages in use according to GitHub, particularly for client–server web applications, with a reported 9 million developers. Java was originally developed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
picture info	C Sharp (programming Language) C# (pronounced ) is a general-purpose, high-level multi-paradigm programming language. C# encompasses static typing, strong typing, lexically scoped, imperative, declarative, functional, generic, object-oriented (class-based), and component-oriented programming disciplines. The C# programming language was designed by Anders Hejlsberg from Microsoft in 2000 and was later approved as an international standard by Ecma (ECMA-334) in 2002 and ISO/IEC (ISO/IEC 23270) in 2003. Microsoft introduced C# along with .NET Framework and Visual Studio, both of which were closed-source. At the time, Microsoft had no open-source products. Four years later, in 2004, a free and open-source project called Mono began, providing a cross-platform compiler and runtime environment for the C# programming language. A decade later, Microsoft released Visual Studio Code (code editor), Roslyn (compiler), and the unified .NET platform (software framework), all of which support C# and are free, open ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]