|
Oak (programming Language)
Oak is a discontinued programming language created by James Gosling in 1989, initially for Sun Microsystems' set-top box project. The language later evolved to become Java. History In 1985, Sun Microsystems was attempting to develop a new technology for programming next generation smart appliances, which Sun expected to be a major new opportunity. The team originally considered using C++, but rejected the idea for several reasons (see Java history). Initially, Gosling attempted to modify and extend C++ but soon abandoned that in favor of creating a new platform called ''Green'' and an entirely new language, which he called Oak, after the oak tree that stood just outside his office. By the summer of 1992, they were able to demonstrate portions of the new platform including the Green OS, the Oak language, the libraries, and the hardware. Their first attempt, demonstrated on September 3, 1992, focused on building a PDA device named ''Star7'' which had a graphical interface ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
James Gosling
James Arthur Gosling (born 19 May 1955) is a Canadian computer scientist, best known as the founder and lead designer behind the Java (programming language), Java programming language. Gosling was elected a member of the National Academy of Engineering in 2004 for the conception and development of the architecture for the Java programming language and for contributions to windowing systems. Early life Gosling was born in Calgary, Calgary, Alberta, to Joyce Morrison and Dave Gosling. He is of English, Welsh, Scottish, and Icelandic descent. Gosling attended William Aberhart High School. While in high school, he wrote some of the software to analyze data from the ISIS (satellite), ISIS 2 satellite, working for the University of Calgary physics department. He received a Bachelor of Science from the University of Calgary and his M.A. and Ph.D. from Carnegie Mellon University, all in computer science. He wrote a version of Emacs called Gosling Emacs (Gosmacs) while working toward ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enumerated Type
In computer programming, an enumerated type (also called enumeration, enum, or factor in the R (programming language), R programming language, a status variable in the JOVIAL programming language, and a categorical variable in statistics) is a data type consisting of a set of named value (computer science), values called ''elements'', ''members'', ''enumeral'', or ''enumerators'' of the type. The enumerator names are usually Identifier (computer languages), identifiers that behave as constant (programming), constants in the language. An enumerated type can be seen as a degenerate tagged union of unit type. A variable (computer science), variable that has been declaration (computer science), declared as having an enumerated type can be assigned any of the enumerators as a value. In other words, an enumerated type has values that are different from each other, and that can be compared and assigned, but are not generally specified by the programmer as having any particular concrete re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Object-oriented Programming Languages
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 implemented in code). In OOP, computer programs are designed by making them out of objects that interact with one another. Many of the most widely used programming languages (such as C++, Java, and Python) support object-oriented programming to a greater or lesser degree, typically as part of multiple paradigms in combination with others such as imperative programming and declarative programming. Significant object-oriented languages include Ada, ActionScript, C++, Common Lisp, C#, Dart, Eiffel, Fortran 2003, Haxe, Java, JavaScript, Kotlin, Logo, MATLAB, Objective-C, Object Pascal, Perl, PHP, Python, R, Raku, Ruby, Scala, SIMSCRIPT, Simula, Smalltalk, Swift, Vala and Visual Basic.NET. History The idea of "objects" in program ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Class-based Programming Languages
Class-based programming, or more commonly class-orientation, is a style of object-oriented programming (OOP) in which inheritance occurs via defining ''classes'' of objects, instead of inheritance occurring via the objects alone (compare prototype-based programming). The most popular and developed model of OOP is a class-based model, instead of an object-based model. In this model, objects are entities that combine ''state'' (i.e., data), ''behavior'' (i.e., procedures, or ''methods'') and '' identity'' (unique existence among all other objects). The structure and behavior of an object are defined by a class, which is a definition, or blueprint, of all objects of a specific type. An object must be explicitly created based on a class and an object thus created is considered to be an instance of that class. An object is similar to a structure, with the addition of method pointers, member access control, and an implicit data member which locates instances of the class (i.e., object ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
C Programming Language Family
C, or c, is the third Letter (alphabet), letter of the Latin alphabet, used in the English alphabet, modern English alphabet, the alphabets of other western European languages and others worldwide. Its name in English is English alphabet#Letter names, ''cee'' (pronounced ), plural ''cees''. History "C" comes from the same letter as "G". The Semitic people, Semites named it gimel. The sign is possibly adapted from an Egyptian hieroglyphs, Egyptian hieroglyph for a Staff-sling, staff sling, which may have been the meaning of the name ''gimel''. Another possibility is that it depicted a camel, the Semitic name for which was ''gamal''. Barry B. Powell, a specialist in the history of writing, states "It is hard to imagine how gimel = "camel" can be derived from the picture of a camel (it may show his hump, or his head and neck!)". In the Etruscan language, plosive consonants had no contrastive phonation, voicing, so the Greek language, Greek 'Gamma, Γ' (Gamma) was adopted int ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Postcondition
In computer programming, a postcondition is a condition or predicate that must always be true just after the execution of some section of code or after an operation in a formal specification. Postconditions are sometimes tested using assertions within the code itself. Often, postconditions are simply included in the documentation of the affected section of code. For example: The result of a factorial is always an integer and greater than or equal to 1. So a program that calculates the factorial of an input number would have postconditions that the result after the calculation be an integer and that it be greater than or equal to 1. Another example: a program that calculates the square root of an input number might have the postconditions that the result be a number and that its square be equal to the input. Postconditions in object-oriented programming In some software design approaches, postconditions, along with preconditions and class invariants, are components of the softw ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Precondition
In computer programming, a precondition is a condition or predicate that must always be true just prior to the execution of some section of code or before an operation in a formal specification. If a precondition is violated, the effect of the section of code becomes undefined and thus may or may not carry out its intended work. Preconditions that are missing, insufficient, or not formally proved (or have an incorrect attempted proof), or are not checked statically or dynamically, can give rise to Security problems, particularly in unsafe languages that are not strongly typed. Often, preconditions are simply included in the documentation of the affected section of code. Preconditions are sometimes tested using guards or assertions within the code itself, and some languages have specific syntactic constructions for doing so. Example The factorial function is only defined where its parameter is an integer greater than or equal to zero. So an implementation of the factorial ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Class Variable
In class-based, object-oriented programming, a class variable is a variable defined in a class of which a single copy exists, regardless of how many instances of the class exist. A class variable is not an instance variable. It is a special type of class attribute (or class property, field, or data member). The same dichotomy between ''instance'' and ''class'' members applies to methods ("member functions") as well; a class may have both instance methods and class methods. Static member variables and static member functions In some languages, class variables and class methods are either statically resolved, not via dynamic dispatch, or their memory statically allocated at compile time (once for the entire class, as static variables), not dynamically allocated at run time (at every instantiation of an object). In other cases, however, either or both of these are dynamic. For example, if classes can be dynamically defined (at run time), class variables of these classes are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Design By Contract
Design by contract (DbC), also known as contract programming, programming by contract and design-by-contract programming, is an approach for designing software. It prescribes that software designers should define formal, precise and verifiable interface specifications for software components, which extend the ordinary definition of abstract data types with preconditions, postconditions and invariants. These specifications are referred to as "contracts", in accordance with a conceptual metaphor with the conditions and obligations of business contracts. The DbC approach assumes all ''client components'' that invoke an operation on a ''server component'' will meet the preconditions specified as required for that operation. Where this assumption is considered too risky (as in multi-channel or distributed computing), the inverse approach is taken, meaning that the ''server component'' tests that all relevant preconditions hold true (before, or while, processing the ''client co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Exception Handling
In computing and computer programming, exception handling is the process of responding to the occurrence of ''exceptions'' – anomalous or exceptional conditions requiring special processing – during the execution of a program. In general, an exception breaks the normal flow of execution and executes a pre-registered ''exception handler''; the details of how this is done depend on whether it is a hardware or software exception and how the software exception is implemented. Exceptions are defined by different layers of a computer system, and the typical layers are CPU-defined interrupts, operating system (OS)-defined signals, programming language-defined exceptions. Each layer requires different ways of exception handling although they may be interrelated, e.g. a CPU interrupt could be turned into an OS signal. Some exceptions, especially hardware ones, may be handled so gracefully that execution can resume where it was interrupted. Definition The definition of an excep ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Java Package
A Java package organizes Java classes into namespaces, providing a unique namespace for each type it contains. Classes in the same package can access each other's package-private and protected members. In general, a package can contain the following kinds of types: classes, interfaces, enumerations, records and annotation An annotation is extra information associated with a particular point in a document or other piece of information. It can be a note that includes a comment or explanation. Annotations are sometimes presented Marginalia, in the margin of book page ... types. A package allows a developer to group classes (and interfaces) together. These classes will all be related in some way – they might all have to do with a specific application or perform a specific set of tasks. Programmers also typically use packages to organize classes belonging to the same category or providing similar functionality. Using packages In a Java source file, the package that this file' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Access Modifiers
Access modifiers (or access specifiers) are keywords in object-oriented languages that set the accessibility of classes, methods, and other members. Access modifiers are a specific part of programming language syntax used to facilitate the encapsulation of components. In C++, there are only three access modifiers. C# extends the number of them to six, while Java has four access modifiers, but three keywords for this purpose. In Java, having no keyword before defaults to the package-private modifier. When the class is declared as public, it is accessible to other classes defined in the same package as well as those defined in other packages. This is the most commonly used specifier for classes. However, a class itself cannot be declared as private. If no access specifier is stated, the default access restrictions will be applied. The class will be accessible to other classes in the same package but will be inaccessible to classes outside the package. When we say that a clas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
