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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),Typeof in "Using the GNU C ... [...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 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 matches the type of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
C (programming Language)
C (''pronounced'' '' – like the letter c'') is a general-purpose programming language. It was created in the 1970s by Dennis Ritchie and remains very widely used and influential. By design, C's features cleanly reflect the capabilities of the targeted Central processing unit, CPUs. It has found lasting use in operating systems code (especially in Kernel (operating system), kernels), device drivers, and protocol stacks, but its use in application software has been decreasing. C is commonly used on computer architectures that range from the largest supercomputers to the smallest microcontrollers and embedded systems. A successor to the programming language B (programming language), B, C was originally developed at Bell Labs by Ritchie between 1972 and 1973 to construct utilities running on Unix. It was applied to re-implementing the kernel of the Unix operating system. During the 1980s, C gradually gained popularity. It has become one of the most widely used programming langu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
C23 (C Standard Revision)
C23, formally ISO/IEC 9899:2024, is the current open standard for the C programming language, which supersedes C17 (standard ISO/IEC 9899:2018). It was started in 2016 informally as C2x, and was published on October 31, 2024. The freely available draft most similar to the one published is document N3220 (see Available texts, below). The first WG14 meeting for the C2x draft was held in October 2019, virtual remote meetings were held in 2020 due to the COVID-19 pandemic, then various teleconference meetings continued to occur through 2024. In C23, the value of __STDC_VERSION__ changes from 201710L to 202311L. The common names "C17" and "C23" reflect these values, which are frozen prior to final adoption, rather than the years in the ISO standards identifiers (9899:2018 and 9899:2024). Features Changes integrated into the latest working draft of C23 are listed below. Standard Library New functions * Add memset_explicit() function in to erase sensitive data, where memory stor ... [...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 metadata, properties, and functions of an object at runtime. Some programming languages also possess that capability (e.g., Java, Python, Julia, and Go). Examples Objective-C In Objective-C, for example, both the generic Object and NSObject (in Cocoa/ OpenStep) provide the method which returns true if the argument to the method is an instance of the specified class. The method analogously returns true if the argument inherits from the specified class. For example, say we have an and an class inheriting from . Now, in the method we can write - (void)eat:(id)sth Now, when is called with a generic object (an ), the function will behave correctly depending ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sizeof
sizeof is a unary operator in the C and C++ programming languages that evaluates to the storage size of an expression or a data type, measured in units sized as char. Consequently, the expression sizeof(char) evaluates to 1. The number of bits of type char is specified by the preprocessor macro CHAR_BIT, defined in the standard include file limits.h. On most modern computing platforms this is eight bits. The result of ''sizeof'' is an unsigned integer that is usually typed as size_t. The operator accepts a single operand which is either a data type expressed as a cast the name of a data type enclosed in parentheses or a non-type expression for which parentheses are not required. 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 is constant, the sizes of even primitive types in C and C++ may be defined differently for different platforms of implementation. For ex ... [...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 metadata, properties, and functions of an object at runtime. Some programming languages also possess that capability (e.g., Java, Python, Julia, and Go). Examples Objective-C In Objective-C, for example, both the generic Object and NSObject (in Cocoa/ OpenStep) provide the method which returns true if the argument to the method is an instance of the specified class. The method analogously returns true if the argument inherits from the specified class. For example, say we have an and an class inheriting from . Now, in the method we can write - (void)eat:(id)sth Now, when is called with a generic object (an ), the function will behave correctly depending ... [...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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Static Type
In computer programming, a type system is a logical system comprising a set of rules that assigns a property called a ''type'' (for example, integer, floating point, string) to every '' term'' (a word, phrase, or other set of symbols). Usually the terms are various language 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 data types, such as "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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
TypeScript
TypeScript (abbreviated as TS) is a high-level programming language that adds static typing with optional type annotations to JavaScript. It is designed for developing large applications and transpiles to JavaScript. It is developed by Microsoft as free and open-source software released under an Apache License 2.0. TypeScript may be used to develop JavaScript applications for both client-side and server-side execution (as with Node.js, Deno or Bun). Multiple options are available for transpiling. The default TypeScript Compiler can be used, or the Babel compiler can be invoked to convert TypeScript to JavaScript. TypeScript supports definition files that can contain type information of existing JavaScript libraries, much like C++ header files can describe the structure of existing object files. This enables other programs to use the values defined in the files as if they were statically typed TypeScript entities. There are third-party header files for popular li ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
JavaScript
JavaScript (), often abbreviated as JS, is a programming language and core technology of the World Wide Web, alongside HTML and CSS. Ninety-nine percent of websites use JavaScript on the client side for webpage behavior. Web browsers have a dedicated JavaScript engine that executes the client code. These engines are also utilized in some servers and a variety of apps. The most popular runtime system for non-browser usage is Node.js. JavaScript is a high-level, often just-in-time–compiled language that conforms to the ECMAScript standard. It has dynamic typing, prototype-based object-orientation, and first-class functions. It is multi-paradigm, supporting event-driven, functional, and imperative programming styles. It has application programming interfaces (APIs) for working with text, dates, regular expressions, standard data structures, and the Document Object Model (DOM). The ECMAScript standard does not include any input/output (I/O), such as netwo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Operator (programming)
In computer programming, an operator is a programming language construct that provides functionality that may not be possible to define as a user-defined function (i.e. sizeof in C) or has syntax different than a function (i.e. infix addition as in a+b). Like other programming language concepts, ''operator'' has a generally accepted, although debatable meaning among practitioners while at the same time each language gives it specific meaning in that context, and therefore the meaning varies by language. Some operators are represented with symbols characters typically not allowed for a function identifier to allow for presentation that is more familiar looking than typical function syntax. For example, a function that tests for greater-than could be named gt, but many languages provide an infix symbolic operator so that code looks more familiar. For example, this: if gt(x, y) then return Can be: if x > y then return Some languages allow a language-defined operator to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
