|
Typeof
typeof, alternately also typeOf, and TypeOf, is an operator provided by several programming languages to determine the data type of a variable. This is useful when constructing programs that must accept multiple types of data without explicitly specifying the type. In languages that support polymorphism and type casting, the typeof operator may have one of two distinct meanings when applied to an object. In some languages, such as Visual Basic, the typeof operator returns the dynamic type of the object. That is, it returns the true, original type of the object, irrespective of any type casting. In these languages, the typeof operator is the method for obtaining run-time type information. In other languages, such as C# or D and, to some degree, in C (as part of nonstandard extensions and proposed standard revisions),https://gcc.gnu.org/onlinedocs/gcc/Typeof.html "Typeof" in Using the GNU Compiler Collection the typeof operator returns the static type of the operand. That is, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Decltype
In the C++ programming language, decltype is a keyword used to query the type of an expression. Introduced in C++11, its primary intended use is in generic programming, where it is often difficult, or even impossible, to express types that depend on Template (C++), template parameters. As generic programming techniques became increasingly popular throughout the 1990s, the need for a type-deduction mechanism was recognized. Many compiler vendors implemented their own versions of the operator, typically called typeof, and some portable implementations with limited functionality, based on existing language features were developed. In 2002, Bjarne Stroustrup proposed that a standardized version of the operator be added to the C++ language, and suggested the name "decltype", to reflect that the operator would yield the "declared type" of an expression. decltype's semantics were designed to cater to both generic library writers and novice programmers. In general, the deduced type matc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Type Introspection
In computing, type introspection is the ability of a program to ''examine'' the type or properties of an object at runtime. Some programming languages possess this capability. Introspection should not be confused with reflection, which goes a step further and is the ability for a program to ''manipulate'' the values, metadata, properties, and functions of an object at runtime. Some programming languages also possess that capability (e.g., Java, Python, Julia, and Go). Examples Ruby Type introspection is a core feature of Ruby. In Ruby, the Object class (ancestor of every class) provides and methods for checking the instance's class. The latter returns true when the particular instance the message was sent to is an instance of a descendant of the class in question. For example, consider the following example code (you can immediately try this with the Interactive Ruby Shell): $ irb irb(main):001:0> A=Class.new => A irb(main):002:0> B=Class.new A => B irb(main):003:0> a=A.n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Typeid
In computer programming, run-time type information or run-time type identification (RTTI) is a feature of some programming languages (such as C++, Object Pascal, and Ada) that exposes information about an object's data type at runtime. Run-time type information may be available for all types or only to types that explicitly have it (as is the case with Ada). Run-time type information is a specialization of a more general concept called type introspection. In the original C++ design, Bjarne Stroustrup did not include run-time type information, because he thought this mechanism was often misused. Overview In C++, RTTI can be used to do safe typecasts, using the dynamic_cast operator, and to manipulate type information at runtime, using the typeid operator and std::type_info class. In Object Pascal, RTTI can be used to perform safe type casts with the as operator, test the class to which an object belongs with the is operator, and manipulate type information at run time with classes c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sizeof
sizeof is a unary operator in the programming languages C and C++. It generates the storage size of an expression or a data type, measured in the number of ''char''-sized units. Consequently, the construct ''sizeof (char)'' is guaranteed to be ''1''. The actual number of bits of type char is specified by the preprocessor macro , defined in the standard include file limits.h. On most modern computing platforms this is eight bits. The result of ''sizeof'' has an unsigned integer type that is usually denoted by size_t. The operator has a single operand, which is either an expression or the cast of a data type, which is a data type enclosed in parentheses. Data types may not only be primitive types, such as integer and floating-point types, but also pointer types, and compound datatypes ( unions, structs, and C++ classes). Purpose Many programs must know the storage size of a particular datatype. Though for any given implementation of C or C++ the size of a particular datatype i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Run-time Type Information
In computer programming, run-time type information or run-time type identification (RTTI) is a feature of some programming languages (such as C++, Object Pascal, and Ada) that exposes information about an object's data type at runtime. Run-time type information may be available for all types or only to types that explicitly have it (as is the case with Ada). Run-time type information is a specialization of a more general concept called type introspection. In the original C++ design, Bjarne Stroustrup did not include run-time type information, because he thought this mechanism was often misused. Overview In C++, RTTI can be used to do safe typecasts, using the dynamic_cast operator, and to manipulate type information at runtime, using the typeid operator and std::type_info class. In Object Pascal, RTTI can be used to perform safe type casts with the as operator, test the class to which an object belongs with the is operator, and manipulate type information at run time with classes c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Type Conversion
In computer science, type conversion, type casting, type coercion, and type juggling are different ways of changing an expression from one data type to another. An example would be the conversion of an integer value into a floating point value or its textual representation as a string, and vice versa. Type conversions can take advantage of certain features of type hierarchies or data representations. Two important aspects of a type conversion are whether it happens ''implicitly'' (automatically) or ''explicitly'', and whether the underlying data representation is converted from one representation into another, or a given representation is merely ''reinterpreted'' as the representation of another data type. In general, both primitive and compound data types can be converted. Each programming language has its own rules on how types can be converted. Languages with strong typing typically do little implicit conversion and discourage the reinterpretation of representations, wh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Object (computer Science)
In computer science, an object can be a variable, a data structure, a function, or a method. As regions of memory, they contain value and are referenced by identifiers. In the object-oriented programming paradigm, ''object'' can be a combination of variables, functions, and data structures; in particular in class-based variations of the paradigm it refers to a particular instance of a class. In the relational model of database management, an object can be a table or column, or an association between data and a database entity (such as relating a person's age to a specific person). Object-based languages An important distinction in programming languages is the difference between an object-oriented language and an object-based language. A language is usually considered object-based if it includes the basic capabilities for an object: identity, properties, and attributes. A language is considered object-oriented if it is object-based and also has the capability of poly ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Visual Basic , an Active Scripting language
{{SIA ...
Visual Basic is a name for a family of programming languages from Microsoft. It may refer to: * Visual Basic .NET (now simply referred to as "Visual Basic"), the current version of Visual Basic launched in 2002 which runs on .NET * Visual Basic (classic), the original Visual Basic supported from 1991–2008 * Embedded Visual Basic, the classic version geared toward embedded applications * Visual Basic for Applications, an implementation of Visual Basic 6 built into programs such as Microsoft Office and used for writing macros * VBScript VBScript (''" Microsoft Visual Basic Scripting Edition"'') is an Active Scripting language developed by Microsoft that is modeled on Visual Basic. It allows Microsoft Windows system administrators to generate powerful tools for managing comput ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MSDN
Microsoft Developer Network (MSDN) was the division of Microsoft responsible for managing the firm's relationship with developers and testers, such as hardware developers interested in the operating system (OS), and software developers developing on the various OS platforms or using the API or scripting languages of Microsoft's applications. The relationship management is situated in assorted media: web sites, newsletters, developer conferences, trade media, blogs and DVD distribution. Starting in January 2020, the website is fully integrated with Microsoft Docs. Websites MSDN's primary web presence at ''msdn.microsoft.com'' is a collection of sites for the developer community that provide information, documentation, and discussion that is authored both by Microsoft and by the community at large. Recently, Microsoft has placed emphasis on incorporation of forums, blogs, library annotations and social bookmarking to make MSDN an open dialog with the developer community rather ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dynamic Type
In computer programming, a type system is a logical system comprising a set of rules that assigns a property called a type to every "term" (a word, phrase, or other set of symbols). Usually the terms are various constructs of a computer program, such as variables, expressions, functions, or modules. A type system dictates the operations that can be performed on a term. For variables, the type system determines the allowed values of that term. Type systems formalize and enforce the otherwise implicit categories the programmer uses for algebraic data types, data structures, or other components (e.g. "string", "array of float", "function returning boolean"). Type systems are often specified as part of programming languages and built into interpreters and compilers, although the type system of a language can be extended by optional tools that perform added checks using the language's original type syntax and grammar. The main purpose of a type system in a programming language ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Programming Language
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 Programming language implementation, implementation that is treated as a reference implementation, 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 lan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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, op ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
