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Include Directive
An include directive instructs a text file processor to replace the directive text with the content of a specified file. The act of including may be logical in nature. The processor may simply process the include file content at the location of the directive without creating a combined file. Different processors may use different syntax. The C preprocessor (used with C, C++ and in other contexts) defines an include directive as a line that starts #include and is followed by a file specification. COBOL defines an include directive indicated by copy in order to include a copybook. Generally, for C/C++ the include directive is used to include a header file, but can include any file. Although relatively uncommon, it is sometimes used to include a body file such as a .c file. The include directive can support encapsulation and reuse. Different parts of a system can be segregated into logical groupings yet rely on one another via file inclusion. C and C++ are designed to lever ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Text Processing
In computing, the term text processing refers to the theory and practice of automating the creation or manipulation of electronic text. ''Text'' usually refers to all the alphanumeric characters specified on the keyboard of the person engaging the practice, but in general ''text'' means the abstraction layer immediately above the standard character encoding of the target text. The term ''processing'' refers to automated (or mechanized) processing, as opposed to the same manipulation done manually. Text processing involves computer commands which invoke content, content changes, and cursor movement, for example to * search and replace * format * generate a processed report of the content of, or * filter a file or report of a text file. The text processing of a regular expression is a virtual editing machine, having a primitive programming language that has named registers (identifiers), and named positions in the sequence of characters comprising the text. Using these, the "text p ... [...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] |
File Name Extension
A filename extension, file name extension or file extension is a suffix to the name of a computer file (for example, .txt, .mp3, .exe) that indicates a characteristic of the file contents or its intended use. A filename extension is typically delimited from the rest of the filename with a full stop (period), but in some systems it is separated with spaces. Some file systems, such as the FAT file system used in DOS, implement filename extensions as a feature of the file system itself and may limit the length and format of the extension, while others, such as Unix file systems, the VFAT file system, and NTFS, treat filename extensions as part of the filename without special distinction. Operating system and file system support The Multics file system stores the file name as a single string, not split into base name and extension components, allowing the "." to be just another character allowed in file names. It allows for variable-length filenames, permitting more than one do ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
C++ Standard Library
The C standard library, sometimes referred to as libc, is the standard library for the C programming language, as specified in the ISO C standard.ISO/ IEC (2018). '' ISO/IEC 9899:2018(E): Programming Languages - C §7'' Starting from the original ANSI C standard, it was developed at the same time as the C POSIX library, which is a superset of it. Since ANSI C was adopted by the International Organization for Standardization, the C standard library is also called the ISO C library. The C standard library provides macros, type definitions and functions for tasks such as string manipulation, mathematical computation, input/output processing, memory management, and input/output. Application programming interface (API) Header files The application programming interface (API) of the C standard library is declared in a number of header files. Each header file contains one or more function declarations, data type definitions, and macros. After a long period of stability, t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
C Standard Library
The C standard library, sometimes referred to as libc, is the standard library for the C (programming language), C programming language, as specified in the ISO C standard.International Organization for Standardization, ISO/International Electrotechnical Commission, IEC (2018). ''C17 (C standard revision), ISO/IEC 9899:2018(E): Programming Languages - C §7'' Starting from the original ANSI C standard, it was developed at the same time as the C POSIX library, which is a superset of it. Since ANSI C was adopted by the International Organization for Standardization, the C standard library is also called the ISO C library. The C standard library provides macro (computer science), macros, Data type, type definitions and Function (computer programming), functions for tasks such as character string (computer science), string manipulation, mathematical computation, input/output processing, memory management, and input/output. Application programming interface (API) Header files The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Include Guard
In the C and C++ programming languages, an #include guard, sometimes called a macro guard, header guard or file guard, is a way to avoid the problem of ''double inclusion'' when dealing with the include directive. The C preprocessor processes inclusion directives like #include "Foo.h" to include "Foo.h" and transcludes the code of that file into a copy of the main file often called the translation unit. However, if an #include directive for a given file appears multiple times during compilation, the code will effectively be duplicated in that file. If the included file includes a definition, this can cause a compilation error due to the One Definition Rule, which says that definitions (such as the definition of a class) cannot be duplicated in a translation unit. #include guards prevent this by defining a preprocessor macro when a header is first included. In the event that header file is included a second time, the #include guard will prevent the actual code within that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Class Implementation File
In object-oriented programming, a class implementation file is often used to contain the implementation code for the method(s) of a class. Programming languages like C++ and Objective-C make use of these implementation files so as to separate the interface and implementation of these methods. Motivation Using this structure, a class definition file containing the declaration of the class and its members is also created. If the class definition has been included and the implementation file for its methods is available, the user can instantiate an object of the class. The purpose of this structure is to keep the implementation code hidden, but allow the user to view the design. Users make use of the public interface of an object so as to make creating objects as simple as possible, ensuring that client code does not distract the user with unnecessary details of the class's implementation. This allows the user the information needed to use the class effectively, but prevents him o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Macro (computer Science)
In computer programming, a macro (short for "macro instruction"; ) is a rule or pattern that specifies how a certain input should be mapped to a replacement output. Applying a macro to an input is known as macro expansion. The input and output may be a sequence of lexical tokens or characters, or a syntax tree. Character macros are supported in software applications to make it easy to invoke common command sequences. Token and tree macros are supported in some programming languages to enable code reuse or to extend the language, sometimes for domain-specific languages. Macros are used to make a sequence of computing instructions available to the programmer as a single program statement, making the programming task less tedious and less error-prone. Thus, they are called "macros" because a "big" block of code can be expanded from a "small" sequence of characters. Macros often allow positional or keyword parameters that dictate what the conditional assembler program gen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Variable (computer Science)
In computer programming, a variable is an abstract storage location paired with an associated symbolic name, which contains some known or unknown quantity of data or object referred to as a '' value''; or in simpler terms, a variable is a named container for a particular set of bits or type of data (like integer, float, string, etc...). A variable can eventually be associated with or identified by a memory address. The variable name is the usual way to reference the stored value, in addition to referring to the variable itself, depending on the context. This separation of name and content allows the name to be used independently of the exact information it represents. The identifier in computer source code can be bound to a value during run time, and the value of the variable may thus change during the course of program execution. Variables in programming may not directly correspond to the concept of variables in mathematics. The latter is abstract, having no reference ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Class (computer Science)
In object-oriented programming, a class defines the shared aspects of objects created from the class. The capabilities of a class differ between programming languages, but generally the shared aspects consist of state ( variables) and behavior ( methods) that are each either associated with a particular object or with all objects of that class. Object state can differ between each instance of the class whereas the class state is shared by all of them. The object methods include access to the object state (via an implicit or explicit parameter that references the object) whereas class methods do not. If the language supports inheritance, a class can be defined based on another class with all of its state and behavior plus additional state and behavior that further specializes the class. The specialized class is a ''sub-class'', and the class it is based on is its ''superclass''. Attributes Object lifecycle As an instance of a class, an object is constructed from a class via '' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Function (computer Programming)
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] |
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] |
