|
One Definition Rule
The One Definition Rule (ODR) is an important rule of the C++ programming language that prescribes that classes/structs and non-inline functions cannot have more than one definition in the entire program and template and types cannot have more than one definition by translation unit. It is defined in the ISO C++ Standard (ISO/IEC 14882) 2003, at section 3.2. Summary In short, the ODR states that: #In any translation unit, a template, type, function, or object can have no more than one definition. Some of these can have any number of declarations. A definition provides an instance. #In the entire program, an object or non-inline function cannot have more than one definition; if an object or function is used, it must have exactly one definition. You can declare an object or function that is never used, in which case you don't have to provide a definition. In no event can there be more than one definition. #Some things, like types, templates, and extern inline functions, can be de ... [...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 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 defini ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Header File
Many programming languages and other computer files have a directive, often called include (sometimes copy or import), that causes the contents of the specified file to be inserted into the original file. These included files are called copybooks or s. There are over one thousand C library files and they are often used to define the physical layout of program data, pieces of procedural code, and/or forward declarations while promoting encapsulation and the reuse of code or data. Header files In computer programming, a header file is a file that allows programmers to separate certain elements of a program's source code into reusable files. Header files commonly contain forward declarations of classes, subroutines, variables, and other identifiers. Programmers who wish to declare standardized identifiers in more than one source file can place such identifiers in a single header file, which other code can then include whenever the header contents are required. This is to keep the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Include Directive
Many programming languages and other computer files have a directive, often called include (sometimes copy or import), that causes the contents of the specified file to be inserted into the original file. These included files are called copybooks or s. There are over one thousand C library files and they are often used to define the physical layout of program data, pieces of procedural code, and/or forward declarations while promoting encapsulation and the reuse of code or data. Header files In computer programming, a header file is a file that allows programmers to separate certain elements of a program's source code into reusable files. Header files commonly contain forward declarations of classes, subroutines, variables, and other identifiers. Programmers who wish to declare standardized identifiers in more than one source file can place such identifiers in a single header file, which other code can then include whenever the header contents are required. This is to keep the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
C++11
C++11 is a version of the ISO/IEC 14882 standard for the C++ programming language. C++11 replaced the prior version of the C++ standard, called C++03, and was later replaced by C++14. The name follows the tradition of naming language versions by the publication year of the specification, though it was formerly named ''C++0x'' because it was expected to be published before 2010. Although one of the design goals was to prefer changes to the libraries over changes to the core language, C++11 does make several additions to the core language. Areas of the core language that were significantly improved include multithreading support, generic programming support, uniform initialization, and performance. Significant changes were also made to the C++ Standard Library, incorporating most of the C++ Technical Report 1 (TR1) libraries, except the library of mathematical special functions. C++11 was published as ''ISO/IEC 14882:2011'' in September 2011 and is available for a fee. The worki ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Template (programming)
Templates are a feature of the C++ programming language that allows functions and classes to operate with generic types. This allows a function or class to work on many different data types without being rewritten for each one. The C++ Standard Library provides many useful functions within a framework of connected templates. Major inspirations for C++ templates were the parameterized modules provided by CLU and the generics provided by Ada. Technical overview There are three kinds of templates: ''function templates'', ''class templates'' and, since C++14, ''variable templates''. Since C++11, templates may be either variadic or non-variadic; in earlier versions of C++ they are always non-variadic. Function templates A ''function template'' behaves like a function except that the template can have arguments of many different types (see example). In other words, a function template represents a family of functions. The format for declaring function templates with type para ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Switch Statement
In computer programming languages, a switch statement is a type of selection control mechanism used to allow the value of a variable or expression to change the control flow of program execution via search and map. Switch statements function somewhat similarly to the if statement used in programming languages like C/C++, C#, Visual Basic .NET, Java and exists in most high-level imperative programming languages such as Pascal, Ada, C/C++, C#, Visual Basic .NET, Java, and in many other types of language, using such keywords as switch, case, select or inspect. Switch statements come in two main variants: a structured switch, as in Pascal, which takes exactly one branch, and an unstructured switch, as in C, which functions as a type of goto. The main reasons for using a switch include improving clarity, by reducing otherwise repetitive coding, and (if the heuristics permit) also offering the potential for faster execution through easier compiler optimization in many cases. His ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Array Data Structure
In computer science, an array is a data structure consisting of a collection of ''elements'' (values or variables), each identified by at least one ''array index'' or ''key''. An array is stored such that the position of each element can be computed from its index tuple by a mathematical formula. The simplest type of data structure is a linear array, also called one-dimensional array. For example, an array of ten 32-bit (4-byte) integer variables, with indices 0 through 9, may be stored as ten words at memory addresses 2000, 2004, 2008, ..., 2036, (in hexadecimal: 0x7D0, 0x7D4, 0x7D8, ..., 0x7F4) so that the element with index ''i'' has the address 2000 + (''i'' × 4). The memory address of the first element of an array is called first address, foundation address, or base address. Because the mathematical concept of a matrix can be represented as a two-dimensional grid, two-dimensional arrays are also sometimes called "matrices". In some cases the term "vector" is used in comp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Constant Expression
Constant or The Constant may refer to: Mathematics * Constant (mathematics), a non-varying value * Mathematical constant, a special number that arises naturally in mathematics, such as or Other concepts * Control variable or scientific constant, in experimentation the unchanging or constant variable * Physical constant, a physical quantity generally believed to be universal and unchanging * Constant (computer programming), a value that, unlike a variable, cannot be reassociated with a different value * Logical constant, a symbol in symbolic logic that has the same meaning in all models, such as the symbol "=" for "equals" People * Constant (given name) * Constant (surname) * John, Elector of Saxony (1468–1532), known as John the Constant * Constant Nieuwenhuys (1920-2005), better known as Constant Places * Constant, Barbados, a populated place Arts and entertainment * " The Constant", a 2008 episode of the television show ''Lost'' * ''The Constant'' (Story of the Year ... [...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] |
1998(E): Programming Languages - C++
1998 was designated as the ''International Year of the Ocean''. Events January * January 6 – The '' Lunar Prospector'' spacecraft is launched into orbit around the Moon, and later finds evidence for frozen water, in soil in permanently shadowed craters near the Moon's poles. * January 11 – Over 100 people are killed in the Sidi-Hamed massacre in Algeria. * January 12 – Nineteen European nations agree to forbid human cloning. * January 17 – The ''Drudge Report'' breaks the story about U.S. President Bill Clinton's alleged affair with Monica Lewinsky, which will lead to the United States House of Representatives, House of Representatives' impeachment of him. February * February 3 – Cavalese cable car disaster (1998), Cavalese cable car disaster: A United States military pilot causes the deaths of 20 people near Trento, Italy, when his low-flying EA-6B Prowler severs the cable of a cable-car. * February 4 – The 5.9 February 1998 Afghanistan earthquake, Afghanis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Namespace
In computing, a namespace is a set of signs (''names'') that are used to identify and refer to objects of various kinds. A namespace ensures that all of a given set of objects have unique names so that they can be easily identified. Namespaces are commonly structured as hierarchies to allow reuse of names in different contexts. As an analogy, consider a system of naming of people where each person has a given name, as well as a family name shared with their relatives. If the first names of family members are unique only within each family, then each person can be uniquely identified by the combination of first name and family name; there is only one Jane Doe, though there may be many Janes. Within the namespace of the Doe family, just "Jane" suffices to unambiguously designate this person, while within the "global" namespace of all people, the full name must be used. Prominent examples for namespaces include file systems, which assign names to files. Some programming languages ... [...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] |
