Datatype

Information about Datatype

In programming languages a data type defines a set of values and the allowable operations on those values^[1]. For example, in the Java programming language, the "int" type represents the set of 32-bit integers ranging in value from -2,147,483,648 to 2,147,483,647, and the operations such as addition, subtraction, and multiplication that can be performed on integers. Almost all programming languages explicitly include the notion of data type, though different languages may use different terminology. Common data types in programming languages include those that represent integers, floating point numbers, and characters, and a language may support many more. Most programming languages also allow the programmer to define additional data types, usually by combining multiple elements of other types and defining the valid operations of the new data type. For example, a programmer might create a new data type named "Person" that specifies that data interpreted as Person would include a name and a date of birth.

A data type can also be thought of as a constraint placed upon the interpretation of data in a type system, describing representation, interpretation and structure of values or objects stored in computer memory. The type system uses data type information to check correctness of computer programs that access or manipulate the data.

Machine data types

All data in computers based on digital electronics is represented as bits (alternatives 0 and 1) on the lowest level. The smallest addressable unit of data is a group of bits called a byte (usually an octet, which is 8 bits). The unit processed by machine code instructions is called a word (as of 2006, typically 32 or 64 bits). Most instructions interpret the word as a binary number, such that a 32-bit word can represent unsigned integer values from 0 to $\text{[math]}$ or signed integer values from $\text{[math]}$ to $\text{[math]}$ . Because of two's complement, the machine language and machine don't need to distinguish between these unsigned and signed data types for the most part.

There is a specific set of arithmetic instructions that use a different interpretation of the bits in word as a floating-point number.

Primitive types

Main article: Primitive type

Composite types

Main article: Composite type

Further information: Tuple

Further information: Array

Further information: Storage record

Further information: Object composition

Abstract data types

Main article: Abstract data type

Pointer and reference types

Main article: Reference (computer science)

Further information: Pointer

Algebraic types

Main article: Algebraic data type

Object types

Main article: Object (computer science)

Further information: Class (computer science)

Function types

Main article: Function type

Notes

1. ^ [1]

References

Luca Cardelli, Peter Wegner. On Understanding Types, Data Abstraction, and Polymorphism, http://citeseer.ist.psu.edu/cardelli85understanding.html from Computing Surveys, (December, 1985)

A programming language is an artificial language that can be used to control the behavior of a machine, particularly a computer. Programming languages, like natural languagess, are defined by syntactic and semantic rules which describe their structure and meaning respectively.
..... Click the link for more information.

Java

Paradigm: Object-oriented, structured, imperative
Appeared in: 1995
Designed by: Sun Microsystems
Typing discipline: Static, strong, safe, nominative
Major implementations: Numerous
Influenced by: Objective-C, C++, Smalltalk, Eiffel,^[1]
..... Click the link for more information.

In computer science, a type system defines how a programming language classifies values and expressions into types, how it can manipulate those types and how they interact.
..... Click the link for more information.

In computer science, a value is a sequence of bits that is interpreted according to some data type. It is possible for the same sequence of bits to have different values, depending on the type used to interpret its meaning.
..... Click the link for more information.

In the programming paradigm of object-oriented programming, an object is the individual run-time unit that is used as the basic building block of programs. These objects act on each other, as opposed to a traditional view in which a program may be seen as a collection of functions,
..... Click the link for more information.

In theoretical computer science, correctness of an algorithm is asserted when it is said that the algorithm is correct with respect to a specification. Functional correctness refers to the input-output behaviour of the algorithm (i.e.
..... Click the link for more information.

BIT is an acronym for:

Bannari amman Institute of Technology
Bangalore Institute of Technology
Beijing Institute of Technology
Benzisothiazolinone
Bilateral Investment Treaty
Bhilai Institute of Technology - Durg

..... Click the link for more information.

byte (pronounced /baɪt/) is a unit of measurement of information storage, most often consisting of eight bits. In many computer architectures it is a unit of memory addressing.
..... Click the link for more information.

In computing, an octet is a grouping of eight bits.

In France, French Canada and Romania, the word octet usually means byte; a megabyte (MB) is called a megaoctet in France, Romania and also French Canada. Bit and Byte are homophones in the French language.
..... Click the link for more information.

Machine code or machine language is a system of instructions and data directly executed by a computer's central processing unit. Machine code is the lowest-level of abstraction for representing a computer program.
..... Click the link for more information.

word" is a term for the natural unit of data used by a particular computer design. A word is simply a fixed-sized group of bits that are handled together by the machine. The number of bits in a word (the word size or word length
..... Click the link for more information.

binary numeral system, or base-2 number system, is a numeral system that represents numeric values using two symbols, usually 0 and 1. More specifically, the usual base-2 system is a positional notation with a radix of 2.
..... Click the link for more information.

The two's complement of a binary number is defined as the value obtained by subtracting the number from a large power of two (specifically, from 2^N for an N-bit two's complement).
..... Click the link for more information.

In computing, floating-point is a numerical-representation system in which a string of digits (or bits) represents a real number. The most commonly encountered representation is that defined by the IEEE 754 Standard.
..... Click the link for more information.

In computer science, primitive types — as distinct from composite types — are data types provided by a programming language as basic building blocks. Primitive types are also known as built-in types or basic types.
..... Click the link for more information.

In computer science, composite types are datatypes which can be constructed in a programming language out of that language's primitive types and other composite types. The act of constructing a composite type is known as composition.
..... Click the link for more information.

For the musical term, see .

In mathematics, a tuple is a finite sequence (also known as an "ordered list") of objects, each of a specified type. A tuple containing n objects is known as an "n-tuple".
..... Click the link for more information.

array is a data structure consisting of a group of elements that are accessed by indexing. In most programming languages each element has the same data type and the array occupies a contiguous area of storage. Most programming languages have a built-in array data type.
..... Click the link for more information.

In computer science, a storage record is:

A group of related data, words, or fields treated as a meaningful unit; for instance, a Name, Address, and Telephone Number can be a "Personal Record".

..... Click the link for more information.

In computer science, object composition (not to be confused with function composition) is a way and practice to combine simple objects or data types into more complex ones.
..... Click the link for more information.

In computing, an abstract data type (ADT) is a specification of a set of data and the set of operations that can be performed on the data. Such a data type is abstract in the sense that it is independent of various concrete implementations.
..... Click the link for more information.

reference is an object containing information which refers to data stored elsewhere, as opposed to containing the data itself. Accessing the value referred to by a reference is called dereferencing it.
..... Click the link for more information.

pointer is a programming language data type whose value refers directly to (or “points to”) another value stored elsewhere in the computer memory using its address. Obtaining the value to which a pointer refers is called dereferencing the pointer.
..... Click the link for more information.

In computer programming, an algebraic data type is a datatype each of whose values is data from other datatypes wrapped in one of the constructors of the datatype. Any wrapped data is an argument to the constructor.
..... Click the link for more information.

This article or section may be confusing or unclear for some readers.
Please [improve the article] or discuss this issue on the talk page. This article has been tagged since December 2006.
..... Click the link for more information.

Type signature is a term that is used in computer programming.

A type signature defines the inputs and outputs for a function or method. A type signature includes at least the function name and the number of its parameters.
..... Click the link for more information.

In mathematics, logic and computer science, type theory is any of several formal systems that can serve as alternatives to naive set theory, or the study of such formalisms in general.
..... Click the link for more information.

This article is copied from an article on Wikipedia.org - the free encyclopedia created and edited by online user community. The text was not checked or edited by anyone on our staff. Although the vast majority of the wikipedia encyclopedia articles provide accurate and timely information please do not assume the accuracy of any particular article. This article is distributed under the terms of GNU Free Documentation License.

Herod_Archelaus

iPedia Free Information Center