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Forward Declaration
In computer programming, a forward declaration is a declaration of an identifier (denoting an entity such as a type, a variable, a constant, or a function) for which the programmer has not yet given a complete definition. It is required for a compiler to know certain properties of an identifier (size for memory allocation, data type for type checking, such as type signature of functions), but it isn't required to know some other details, like the particular value it holds (in case of variables or constants) or definition (in the case of functions). This is particularly useful for one-pass compilers and separate compilation. Forward declaration is used in languages that require declaration before use; it is necessary for mutual recursion in such languages, as it is impossible to define such functions (or data structures) without a forward reference in one definition: one of the functions (respectively, data structures) must be declared first. It is also useful to allow flexible c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computer Programming
Computer programming or coding is the composition of sequences of instructions, called computer program, programs, that computers can follow to perform tasks. It involves designing and implementing algorithms, step-by-step specifications of procedures, by writing source code, code in one or more programming languages. Programmers typically use high-level programming languages that are more easily intelligible to humans than machine code, which is directly executed by the central processing unit. Proficient programming usually requires expertise in several different subjects, including knowledge of the Domain (software engineering), application domain, details of programming languages and generic code library (computing), libraries, specialized algorithms, and Logic#Formal logic, formal logic. Auxiliary tasks accompanying and related to programming include Requirements analysis, analyzing requirements, Software testing, testing, debugging (investigating and fixing problems), imple ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Link Time
In computer science, link time refers to the period of time, during the creation of a computer program, in which a linker is being applied to that program. Link time occurs after compile time and before runtime (when a program is executed). It is common to speak of ''link time operations'' (the operations performed by a linker) or ''link time requirements'' (programming language requirements that must be met by compiled source code for it to be successfully linked). Link time operations The operations performed at link time usually include fixing up the addresses of externally referenced objects and functions, various kinds of cross module checks (e.g. type checks on externally visible identifiers and in some languages instantiation of templates). Some optimizing compilers delay code generation until link time because it is here that information about a complete program is available to them. Resolving external variables in a program is also done at link time. The link-tim ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Member Variable
In object-oriented programming Object-oriented programming (OOP) is a programming paradigm based on the concept of '' objects''. Objects can contain data (called fields, attributes or properties) and have actions they can perform (called procedures or methods and impl ..., a member variable (sometimes called a member field) is a variable that is associated with a specific object, and accessible for all its methods (''member functions''). In class-based programming languages, these are distinguished into two types: '' class variables'' (also called ''static member variables''), where only one copy of the variable is shared with all instances of the class; and '' instance variables'', where each instance of the class has its own independent copy of the variable. Examples C++ class Foo ; int main () Java public class Program public class Foo Python class Foo: def __init__(self): self._bar = 0 @property def bar(self): ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Circular Reference
A circular reference (or reference cycle) is a series of references where the last object references the first, resulting in a closed loop. Simple example A newcomer asks a local where the town library is. "Just in front of the post office," says the local. The newcomer nods, and follows up: "But where is the post office?" "Why, that's simple," replies the local. "It's just behind the library!" In language A circular reference is not to be confused with the logical fallacy of a circular argument. Although a circular reference will often be unhelpful and reveal no information, such as two entries in a book index referring to each other, it is not necessarily so that a circular reference is of no use. Dictionaries, for instance, must always ultimately be a circular reference since all words in a dictionary are defined in terms of other words, but a dictionary nevertheless remains a useful reference. Sentences containing circular references can still be meaningful: :''Her b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Objective-C
Objective-C is a high-level general-purpose, object-oriented programming language that adds Smalltalk-style message passing (messaging) to the C programming language. Originally developed by Brad Cox and Tom Love in the early 1980s, it was selected by NeXT for its NeXTSTEP operating system. Due to Apple macOS’s direct lineage from NeXTSTEP, Objective-C was the standard language used, supported, and promoted by Apple for developing macOS and iOS applications (via their respective application programming interfaces ( APIs), Cocoa and Cocoa Touch) from 1997, when Apple purchased NeXT until the introduction of the Swift language in 2014. Objective-C programs developed for non-Apple operating systems or that are not dependent on Apple's APIs may also be compiled for any platform supported by GNU GNU Compiler Collection (GCC) or LLVM/ Clang. Objective-C source code 'messaging/implementation' program files usually have filename extensions, while Objective-C 'header/ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Identifier
An identifier is a name that identifies (that is, labels the identity of) either a unique object or a unique ''class'' of objects, where the "object" or class may be an idea, person, physical countable object (or class thereof), or physical mass noun, noncountable substance (or class thereof). The abbreviation ID often refers to identity, identification (the process of identifying), or an identifier (that is, an instance of identification). An identifier may be a word, number, letter, symbol, or any combination of those. The words, numbers, letters, or symbols may follow an code, encoding system (wherein letters, digits, words, or symbols ''stand for'' [represent] ideas or longer names) or they may simply be arbitrary. When an identifier follows an encoding system, it is often referred to as a code or id code. For instance the ISO/IEC 11179 metadata registry standard defines a code as ''system of valid symbols that substitute for longer values'' in contrast to identifiers wi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Niklaus Wirth
Niklaus Emil Wirth ( IPA: ) (15 February 1934 – 1 January 2024) was a Swiss computer scientist. He designed several programming languages, including Pascal, and pioneered several classic topics in software engineering. In 1984, he won the Turing Award, generally recognized as the highest distinction in computer science, "for developing a sequence of innovative computer languages". Early life and education Niklaus Emil Wirth was born in Winterthur, Switzerland, on 15 February 1934. He was the son of Hedwig (née Keller) and Walter Wirth, a high school teacher. Wirth studied electronic engineering at the Federal Institute of Technology, Zürich (ETH Zürich) from 1954 to 1958, graduating with a Bachelor of Science (B.S.) degree. In 1960, he earned a Master of Science (M.Sc.) from Université Laval in Quebec. Then in 1963, he was awarded a PhD in electrical engineering and computer science (EECS) from the University of California, Berkeley, supervised by computer design pione ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pascal (programming Language)
Pascal is an imperative and procedural programming language, designed by Niklaus Wirth as a small, efficient language intended to encourage good programming practices using structured programming and data structuring. It is named after French mathematician, philosopher and physicist Blaise Pascal. Pascal was developed on the pattern of the ALGOL 60 language. Wirth was involved in the process to improve the language as part of the ALGOL X efforts and proposed a version named ALGOL W. This was not accepted, and the ALGOL X process bogged down. In 1968, Wirth decided to abandon the ALGOL X process and further improve ALGOL W, releasing this as Pascal in 1970. On top of ALGOL's scalars and arrays, Pascal enables defining complex datatypes and building dynamic and recursive data structures such as lists, trees and graphs. Pascal has strong typing on all objects, which means that one type of data cannot be converted to or interpreted as another without explicit conversions ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Function Prototype
In computer programming, a function prototype is a declaration of a function that specifies the function's name and type signature (arity, data types of parameters, and return type), but omits the function body. While a function definition specifies ''how'' the function does what it does (the "implementation"), a function prototype merely specifies its interface, i.e. ''what'' data types go in and come out of it. The term "function prototype" is particularly used in the context of the programming languages C and C++ where placing forward declarations of functions in header files allows for splitting a program into translation units, i.e. into parts that a compiler can separately translate into object files, to be combined by a linker into an executable or a library. The function declaration precedes the function definition, giving details of name, return type, and storage class along with other relevant attributes. Function prototypes can be used when either: * Definin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Subroutine
In computer programming, a function (also procedure, method, subroutine, routine, or subprogram) is a callable unit of software logic that has a well-defined interface and behavior and can be invoked multiple times. Callable units provide a powerful programming tool. The primary purpose is to allow for the decomposition of a large and/or complicated problem into chunks that have relatively low cognitive load and to assign the chunks meaningful names (unless they are anonymous). Judicious application can reduce the cost of developing and maintaining software, while increasing its quality and reliability. Callable units are present at multiple levels of abstraction in the programming environment. For example, a programmer may write a function in source code that is compiled to machine code that implements similar semantics. There is a callable unit in the source code and an associated one in the machine code, but they are different kinds of callable units with different impl ... [...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] |
Multi-pass Compiler
A multi-pass compiler is a type of compiler that processes the source code or abstract syntax tree of a program several times. This is in contrast to a one-pass compiler, which traverses the program only once. Each pass takes the result of the previous pass as the input, and creates an intermediate output. In this way, the (intermediate) code is improved pass by pass, until the final pass produces the final code. Multi-pass compilers are sometimes called wide compilers, referring to the greater scope of the passes: they can "see" the entire program being compiled, instead of just a small portion of it. The wider scope thus available to these compilers allows better Code generation (compiler), code generation (e.g. smaller code size, faster code) compared to the output of one-pass compilers, at the cost of higher compiler time and memory consumption. In addition, some programming language, languages cannot be compiled in a single pass, as a result of their design. Typical multi-pas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
