Unit 2: Objects and Primitive Data

character set

A defined list of characters recognized by the computer hardware and software. Each character is represented by a number. The ASCII character set, for example, uses the numbers 0 through 127 to represent all English characters as well as special control characters.

arithmetic promotion

If one operand is of type "double", then the other operand is promoted to the type double. If Both operands are of type less than "int" , for example (byte,short,char...) ... If no operand of type (double,float ,long ) , then convert to type integer

level of abstraction

The amount of complexity by which a system is viewed or programmed. The higher the level, the less detail. The lower the level, the more detail. The highest level of abstraction is the entire system. The next level would be a handful of components, and so on, while the lowest level could be millions of objects.

floating point division

These algorithms are based on Goldschmidt's division algorithm and provide support for single, double, and extended precision floating- point numbers.

ASCII character set

This character set is utilized to encode characters such as letters, numbers, and punctuation marks, with each character assigned a 7-bit number code. Panda Software. Glossary of Terms.

unicode character set

Unlike ASCII, which uses 7 bits for each character, Unicode uses 16 bits, which means that it can represent more than 65,000 unique characters. This is a bit of overkill for English and Western-European languages, but it is necessary for some other languages, such as Greek, Chinese and Japanese.

string literal

a Java language concept. This is a String literal: "a String literal" A String object is an individual instance of the java.lang.String class. String s1 = "abcde"; String s2 = new String("abcde"); String s3 = "abcde"; All are valid, but have a slight difference.

control characters

a character that does not represent a printable character but serves to initiate a particular action.

operators

a character that represents an action, as for example x is an arithmetic operator that represents multiplication. In computer programs, one of the most familiar sets of operators, the Boolean operators, is used to work with true/false values.

scanner class

a class in java.util, which allows the user to read values of various types. There are far more methods in class Scanner than you will need in this course.

class library

a collection of prewritten class es or coded templates, any of which can be specified and used by a programmer when developing an application program.

expression

a combination of one or more explicit values, constants, variables, operators, and functions that the programming language interprets (according to its particular rules of precedence and of association) and computes to produce ("to return", in a stateful environment) another ...

inheritance

a feature that represents the "is a" relationship between different classes. Inheritance allows a class to have the same behavior as another class and extend or tailor that behavior to provide special action for specific needs.

index

a list of libraries

double

a number with a decimal point (more precise than a float)

class methods

a procedure associated with a message and an object. ... In class-based programming, methods are defined in a class, and objects are instances of a given class.

reference to an object

a relation between objects in which one object designates, or acts as a means by which to connect to or link to, another object. The first object in this relation is said to refer to the second object. ... The second object, the one to which the first object refers, is called the referent of the first object.

escape sequences

a sequence of characters that does not represent itself when used inside a character or string literal, but is translated into another character or a sequence of characters that may be difficult or impossible to represent directly.

delimiters

a sequence of one or more characters used to specify the boundary between separate, independent regions in plain text or other data streams. An example of a delimiter is the comma character, which acts as a field delimiter in a sequence of comma-separated values.

method

a set of code which is referred to by name and can be called (invoked) at any point in a program simply by utilizing the method's name. Think of a method as a subprogram that acts on data and often returns a value. Each method has its own name.

API (application programmer interface)

a set of routines, protocols, and tools for building software applications. Basically, an API specifies how software components should interact. Additionally, APIs are used when programming graphical user interface (GUI) components.

parameter

a special kind of variable in computer programming language that is used to pass information between functions or procedures. The actual information passed is called an argument.

attributes

a specification that defines a property of an object, element, or file. It may also refer to or set the specific value for a given instance of such. For clarity, attributes should more correctly be considered metadata.

import declaration

a statement made to the Australian Customs and Border Protection Service (ACBPS) providing information about imported goods. Import declarations are used to clear goods from Customs control with a value exceeding AUD$1000.

variable

a storage location (identified by a memory address) paired with an associated symbolic name (an identifier), which contains some known or unknown quantity of information referred to as a value.

abstraction

a technique for arranging complexity of computer systems. It works by establishing a level of simplicity on which a person interacts with the system, suppressing the more complex details below the current level.

assignment conversion

a term used with similar meanings in the law of contracts and in the law of real estate. In both instances, it encompasses the transfer of rights held by one party, the assignor, to another party, the assignee.

character literal

a type of literal in programming for the representation of a single character's value within the source code of a computer program. Languages that have a dedicated character data type generally include character literals; these include C, C++, Java, and Visual Basic, but not Python or PHP.

constant

a variable that never changes

boolean

a variable with a value of true or false

int

a whole number

wrapper classes

a wrapper class that encapsulates, hides or wraps data types from the eight primitive data types, so that these can be used to create instantiated objects with methods in another class or in other classes. The primitive wrapper classes are found in the Java API.

overflow

an error that occurs when the computer attempts to handle a number that is too large for it. Every computer has a well-defined range of values that it can represent. If during execution of a program it arrives at a number outside this range, it will experience an overflow error.

object

an instance of a class

binary operator

an operator that operates on two operands and manipulates them to return a result. Operators are represented by special characters or by keywords and provide an easy way to compare numerical values or character strings. Binary operators are presented in the form: Operand1 Operator Operand2.

unary operator

an operator that takes a single operand in an expression or a statement. The unary operators in C# are +, -,!, ~, ++, -- and the cast operator.

standard class library

have access to a subset of APIs, and can be used by apps and libraries that target multiple platforms. .NET Standard class libraries are a merger of the platform-specific and portable library concept into a single model that provides the best of both.

derived classes

inherits all of the member variables and methods of the base class from which it is derived.

widening conversion

int to double

return type

int, boolean, string, etc.

underflow

is a condition in a computer program where the result of a calculation is a number of smaller absolute value than the computer can actually represent in memory on its CPU.

floating point literal

is the significand mutiplied by the number 10 raised to the power of exponent.

operator precedence heirarchy

java has well-defined rules for specifying the order in which the operators in an expression are evaluated when the expression has several operators. For example, multiplication and division have a higher precedence than addition and subtraction. Precedence rules can be overridden by explicit parentheses.

static methods

methods that stay the same; do not change.

primitive data

most basic data types available within the Java language. There are 8: boolean , byte , char , short , int , long , float and double . These types serve as the building blocks of data manipulation in Java. Such types serve only one purpose — containing pure, simple values of a kind.

uninitialized

not initialized

instance

one creation of an object

strongly typed

programming language is one in which each type of data (such as integer, character, hexadecimal, packed decimal, and so forth) is predefined as part of the programming language and all constants or variables defined for a given program must be described with one of the data types.

left-to-right association

reads code from left to right

return (return like value)

returns a value

assignment statement

sets and/or re-sets the value stored in the storage location(s) denoted by a variable name; in other words, it copies a value into the variable. In most imperative programming languages, the assignment statement (or expression) is a fundamental construct.

constructor

something that runs and sets up program in the beginning

literal

taking words in their usual or most basic sense without metaphor or allegory

class

the basic building block of an object-oriented language such as Java--is a template that describes the data and behavior associated with instances of that class. When you instantiate a class you create an object that looks and feels like other instances of the same class.

tokens

the basic component of source code . Character s are categorized as one of five classes of tokens that describe their functions (constants, identifiers, operators, reserved words, and separators) in accordance with the rules of the programming language.

polymorphism

the condition of occurring in several different forms.

rounding errors

the difference between the calculated approximation of a number and its exact mathematical value due to rounding. This is a form of quantization error.

integer division

the mathematical formulation of the outcome of the usual process of division of integers. It asserts that, given two integers, a, the dividend, and b, the divisor, such that b ≠ 0, there are unique integers q, the quotient, and r, the remainder, such that a = bq + r and 0 ≤ r < b. , where.

string concatenation

the operation of joining character strings end-to-end. For example, the concatenation of "snow" and "ball" is "snowball".

software reuse

the process of creating software systems from predefined software components.

behaviours

the way a machine, element, etc. acts or functions

instantiation

to instantiate (to create an instance)

assigns

to set something

casting

type conversion or typecasting refers to changing an entity of one datatype into another. There are two types of conversion: implicit and explicit. The term for implicit type conversion is coercion. Explicit type conversion in some specific way is known as casting.

signed

use gestures to convey information or instructions.

dot operator

used to access deeper files

packages

written programs or procedures or rules and associated documentation pertaining to the operation of a computer system and that are stored in read/write memory. Synonyms: computer software, software, software package, software program, software system Antonyms: computer hardware, hardware.

remainder operator

%

fully qualify

an unambiguous name that specifies which object, function, or variable a call refers to without regard to the context of the call. In a hierarchical structure, a name is fully qualified when it "is complete in the sense that it includes (a) all names in the hierarchic sequence above the given element and (b) the name of the given element itself." Thus fully qualified names explicitly refer to namespaces that would otherwise be implicit because of the scope of the call. While always done to eliminate ambiguity, this can mean different things dependent on context.

standard input stream

are preconnected input and output communication channels between a computer program and its environment when it begins execution. The three input/output (I/O) connections are called standard input (stdin), standard output (stdout) and standard error (stderr).

boolean literal

ata type is a data type, having two values (usually denoted true and false), intended to represent the truth values of logic and Boolean algebra. It is named after George Boole, who first defined an algebraic system of logic in the mid 19th century.

integer literal

can be a decimal, octal, or hexadecimal constant. A prefix specifies the base or radix: 0x or 0X for hexadecimal, 0 for octal, and nothing for decimal. An integer literal can also have a suffix that is a combination of U and L, for unsigned and long, respectively.

immutable

can't be changed

state

current status or condition

narrowing conversion

double to int

encapsulation

enclose (a message or signal) in a set of codes that allow use by or transfer through different computer systems or networks.