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Class Member Function
A class in C++ is a user-defined type or data structure declared with keyword class that has data and functions (also called member variables and member functions) as its members whose access is governed by the three access specifiers ''private'', ''protected'' or ''public''. By default access to members of a C++ class is ''private''. The private members are not accessible outside the class; they can be accessed only through methods of the class. The public members form an interface to the class and are accessible outside the class. Instances of a class data type are known as objects and can contain member variables, constants, member functions, and overloaded operators defined by the programmer. Differences between a structure and a class in C++ In C++, a class defined with the class keyword has private members and base classes by default. A structure is a class defined with the struct keyword.ISO/IEC (2003). '' ISO/IEC 14882:2003(E): Programming Languages - C++ §9 Classes la ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Data Structure Alignment
Data structure alignment is the way data is arranged and accessed in computer memory. It consists of three separate but related issues: data alignment, data structure padding, and packing. The CPU in modern computer hardware performs reads and writes to memory most efficiently when the data is ''naturally aligned'', which generally means that the data's memory address is a multiple of the data size. For instance, in a 32-bit architecture, the data may be aligned if the data is stored in four consecutive bytes and the first byte lies on a 4-byte boundary. ''Data alignment'' is the aligning of elements according to their natural alignment. To ensure natural alignment, it may be necessary to insert some ''padding'' between structure elements or after the last element of a structure. For example, on a 32-bit machine, a data structure containing a 16-bit value followed by a 32-bit value could have 16 bits of ''padding'' between the 16-bit value and the 32-bit value to align the 32-bi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Ampersand
The ampersand, also known as the and sign, is the logogram , representing the conjunction "and". It originated as a ligature of the letters ''et''—Latin for "and". Etymology Traditionally in English, when spelling aloud, any letter that could also be used as a word in itself ("A", "I", and, " O") was prefixed with the Latin expression ('by itself'), as in "per se A". It was also common practice to add the sign at the end of the alphabet as if it were the 27th letter, pronounced as the Latin ''et'' or later in English as ''and''. As a result, the recitation of the alphabet would end in "X, Y, Z, ''and per se and''". This last phrase was routinely slurred to "ampersand" and the term had entered common English usage by 1837. It has been falsely claimed that André-Marie Ampère used the symbol in his widely read publications and that people began calling the new shape "Ampère's and". History The ampersand can be traced back to the 1st century A.D. and the old Roman ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Compiler
In computing, a compiler is a computer program that translates computer code written in one programming language (the ''source'' language) into another language (the ''target'' language). The name "compiler" is primarily used for programs that translate source code from a high-level programming language to a low-level programming language (e.g. assembly language, object code, or machine code) to create an executable program. Compilers: Principles, Techniques, and Tools by Alfred V. Aho, Ravi Sethi, Jeffrey D. Ullman - Second Edition, 2007 There are many different types of compilers which produce output in different useful forms. A '' cross-compiler'' produces code for a different CPU or operating system than the one on which the cross-compiler itself runs. A '' bootstrap compiler'' is often a temporary compiler, used for compiling a more permanent or better optimised compiler for a language. Related software include, a program that translates from a low-level language ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Operator (programming)
In computer programming, operators are constructs defined within programming languages which behave generally like functions, but which differ syntactically or semantically. Common simple examples include arithmetic (e.g. addition with ), comparison (e.g. " greater than" with >), and logical operations (e.g. AND, also written && in some languages). More involved examples include assignment (usually = or :=), field access in a record or object (usually .), and the scope resolution operator (often :: or .). Languages usually define a set of built-in operators, and in some cases allow users to add new meanings to existing operators or even define completely new operators. Syntax Syntactically operators usually contrast to functions. In most languages, functions may be seen as a special form of prefix operator with fixed precedence level and associativity, often with compulsory parentheses e.g. Func(a) (or (Func a) in Lisp). Most languages support programmer-defin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Virtual Inheritance
Virtual inheritance is a C++ technique that ensures only one copy of a base classs member variables are inherited by grandchild derived classes. Without virtual inheritance, if two classes B and C inherit from a class A, and a class D inherits from both B and C, then D will contain two copies of As member variables: one via B, and one via C. These will be accessible independently, using scope resolution. Instead, if classes B and C inherit virtually from class A, then objects of class D will contain only one set of the member variables from class A. This feature is most useful for multiple inheritance, as it makes the virtual base a common subobject for the deriving class and all classes that are derived from it. This can be used to avoid the diamond problem by clarifying ambiguity over which ancestor class to use, as from the perspective of the deriving class (D in the example above) the virtual base (A) acts as though it were the direct base class of D, not a class derived i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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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] |
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Inheritance (computer Science)
In object-oriented programming, inheritance is the mechanism of basing an object or class upon another object ( prototype-based inheritance) or class ( class-based inheritance), retaining similar implementation. Also defined as deriving new classes ( sub classes) from existing ones such as super class or base class and then forming them into a hierarchy of classes. In most class-based object-oriented languages, an object created through inheritance, a "child object", acquires all the properties and behaviors of the "parent object" , with the exception of: constructors, destructor, overloaded operators and friend functions of the base class. Inheritance allows programmers to create classes that are built upon existing classes, to specify a new implementation while maintaining the same behaviors ( realizing an interface), to reuse code and to independently extend original software via public classes and interfaces. The relationships of objects or classes through inheritance gi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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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 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 or her f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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This (computer Science)
this, self, and Me are keywords used in some computer programming languages to refer to the object, class, or other entity of which the currently running code is a part. The entity referred to by these keywords thus depends on the execution context (such as which object is having its method called). Different programming languages use these keywords in slightly different ways. In languages where a keyword like "this" is mandatory, the keyword is the only way to access data and methods stored in the current object. Where optional, they can disambiguate variables and functions with the same name. Object-oriented programming In many object-oriented programming languages, this (also called self or Me) is a variable that is used in instance methods to refer to the object on which they are working. The first OO language, SIMULA 67, used this to explicitly reference the local object. C++ and languages which derive in style from it (such as Java, C#, D, and PHP) also generally use ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Semicolon
The semicolon or semi-colon is a symbol commonly used as orthographic punctuation. In the English language, a semicolon is most commonly used to link (in a single sentence) two independent clauses that are closely related in thought. When a semicolon joins two or more ideas in one sentence, those ideas are then given equal rank. Semicolons can also be used in place of commas to separate the items in a list, particularly when the elements of that list contain commas. The semicolon is one of the least understood of the standard marks, and so it is not as frequently used by many English speakers. In the QWERTY keyboard layout, the semicolon resides in the unshifted homerow beneath the little finger of the right hand and has become widely used in programming languages as a statement separator or ''terminator''. History In 1496, the semicolon is attested in Pietro Bembo's book ' printed by Aldo Manuzio. The punctuation also appears in later writings of Bembo. Moreove ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |