Glossary

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Wiki 1010 Table of Contents

Chapter #

This page contains a glossary of terms used within the wiki along with definitions.

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Table of Contents


Glossary

- A -

  • ACM - Association for Computing Machinery. A non-profit professional organization dedicated to the advancement of computing as a science and a profession.
  • Algorithm - a set of well defined instructions for completing a task, for example: a computer program that calculates the class average would be an algorithm.
  • Application - A program designed to perform specific tasks. Ex. Microsoft Word, Textpad
  • Argument - A value passed to a method's parameter during a method call.
  • Array- An object that can contain many values of the same type.
  • Array Index - An array index refers to a particular storage position in an array.
  • Array Length - Array length means the maximum size of the array.

- B -

  • Binary - A numbering system that uses only the digits 0 and 1. Any number can be represented in binary: 1, 2, 3, 4, 5, ... = 1, 10, 11, 100, 101, ...
  • Bug- A program error is referred to as a bug. See debugging.
  • Bit - The smallest unit of information in a computer, with a value of either 0 or 1.
  • Boolean - A Boolean is a data type that stores one of two possible values: true or false. Booleans are useful to use in conditions because conditions will eventually evaluate to a Boolean value anyway.
  • Byte -The amount of computer memory needed to store one character of a specified size,a single byte consisting of eight bits.

- C -

  • Casting - A means to convert a variable of one data type to a different data type.
  • Char - A char is a data type in Java which can store one letter, digit, or other character.
  • Class - In object oriented languages, such as C++ and Java, a Class represents the definition of a collection of variables and methods pertaining to a certain functional unit or data structure. The Class is in contrast with the Object in that a Class is merely a definition of an Object that has not yet been allocated the necessary memory to function at the program's runtime.
  • Control Statement - A statement that returns a boolean value usually used to denote conditions for an if statement or the end case of a loop.
  • Compiler - The Java compiler is the part of Java that takes the code you have written and converts into a language that can be understood by the Java Virtual Machine (JVM). This is the information contained in the .class files created by the compiler. It is referred to as Java bytecode.
  • Contiguous - Arranged one-after-the-other, with nothing in between.
  • Co-op - A special program at the University of Manitoba that complements your academic terms with relevant work experience in industry. Students who take part in this program normally alternate between eight months of classes followed by four months of work. Please visit the [Co-op] website for more information.

- D -

  • Data Structure - A way of storing data in the computer so that the data can be processed efficiently. Common data structures are array, linked list, queue, stack and tree.
  • debugging- The process of isolating, correcting, and verifying the correction is called debugging.
  • Declaration -A declaration is the process of choosing a variable name for a specific variable. For example int num; is declaring num as an variable of type integer.
  • Double - A double is a data type in Java which can store postive and negative numbers with decimal places, which are more formally called real numbers.

- E -

  • Explicit Cast - A cast that occurs when you specifically tell the Java compiler you want one. This is done by placing the type you are casting to, inside brackets, in front of the name of the variable you are casting from.
  • Else - Used in conjunction with an if statement to execute code if the conditional test of the if statement is false. See if.
  • Else If - Also known as if else statements. Used in conjunction with an if statement to have multiple similar tests and execute code based on the result of those tests. See else if statements and if.

- F -

  • File type - A way of identifying the format of a file. In Windows, the file type is usually shown as an extension - the characters in a filename that appear after the last period. For example, in the file assignment1.java, the extension is java, which represents the Java source code file type.
  • Float - A Float is a java keyword used to describe any number with a decimal part.These numbers are also called floating point numbers. Examples of floating point numbers are 0.45 and 4.9999.
  • For Loop - A For loop is a counted loop that executes a section of code a certain number of times. E.g. Looping through an array to find the maximum value.

- G -

  • GUI - Short for Graphical User Interface, is a graphical (rather than purely textual) user interface to a computer where the user clicks on a visual screen that has icons, windows and menus, by using a pointing device, such as a mouse. GUI is pronounced like "gooey". As you read this, you are looking at the GUI or graphical user interface of your particular Web browser. The term came into existence because the first interactive user interfaces to computers were not graphical; they were text-and-keyboard oriented and usually consisted of commands you had to remember and computer responses that were infamously brief.

- H -

  • Hardware - The physical parts of a computer. Computers are made up of different pieces of hardware, such as CPUs, RAM, hard drives, etc.
  • Hexadecimal - (sometimes abbreviated to hex) A numbering system that uses a total of 16 digits: 0-9, A-F. A-F represent the decimal values 10-15, with the hex value 10 representing 16, hex 11 representing 17, and so on.

- I -

  • If - A Java keyword that is used to perform a conditional test and execute a block of statements if the test evaluates to true.
  • If Else - Also known as else if statements. Used in conjunction with an if statement to have multiple similar tests and execute code based on the result of those tests. See else if statements and if.
  • IEEE - Institute of Electrical and Electronics Engineers. A non-profit professional organization dedicated to the advancements in the field of electronics and electrical engineering.
  • Integer - An integer is a number that can be written without a fraction or a decimal. The data type 'int' in Java can be used to store integers.
  • Implicit - A cast that occurs without explicitly asking for one. That is to say, the statement you create requires a cast and it can be inferred by the Java compiler. Ex. "a string" + intVal will implicitly cast the int value to a string and append it to the string.
  • Index (arrays) - An array index of n will select the nth element of the array.
  • Initialization - is the process of assigning a value to a variable. This variable may be a primitive variable and will hold the value that was assigned to it.

- J -

  • Java virtual machine - Often abbreviated to JVM, the Java virtual machine is a piece of software that runs Java programs. The JVM interprets the Java bytecode created by the Java compiler and creates machine code on-the-fly (as a program is running). See chapter 10, Java In-depth, for more information.
  • JDK - Short for Java Development Kit, is a free software development package from Sun Microsystem's JavaSoft division that implements the basic set of tools needed to write, test and debug Java applications and applets.
  • Journal - A publication of articles submitted by researchers and academics on specific topics in the specific field of study.

- K -

  • Keyword - In Java programming language, some words are set aside as keywords - these words are reserved by the language itself and therefore are not available as names for variables or methods. Examples of Java keywords: if, void, null, and public.
  • Kilobyte - (KB) A unit of storage equal to 2^10 or 1024 bytes.

- L -

  • Loop - A loop is part of a program that is repeated. There are two main types of loops counted and conditional. A counted loop executes a defined number of times and conditional loop executes until a condition is met.

- M -

  • Machine language - The language that a computer understands. It is usually just a series of 0's and 1's (binary digits). Machine language is often referred to as machine code. See chapter 2's further reading for more details.
  • Main Method - The method which Java runs when it is told to execute a class.
  • Method - A method in Java is a grouping of algorithms or operations which can be called upon at once with a method call.
  • Multi-DImensional Array - An array that contains other arrays. These arrays may also contain other arrays, eg. a two-dimensional array is an array of arrays, a three-dimensional aray is an array of arays of arrays, etc.

- N -

  • Nested Method Call - A method call in which another method call is used as an argument.

- O -

  • Object - In object oriented languages, such as C++ and Java, an Object represents a collection of variables and methods pertaining to a certain class of functional unit or data structure. The Object is in contrast with the Class in that an Object is an instance of a Class that has been allocated the necessary memory to function at the program's runtime.
  • Operator - An operator is a symbol used for logical, mathematical or assignment operations, such as =, + or &&.
  • Overflow - A problem which occurs when a data value becomes too large for the variable to hold. This can have devastating and unpredictable results on a program.

- P -

  • Parameter - An input value which that a method expects.
  • Platform - Some sort of framework, either in software or hardware, that runs software. For example, the Windows operating system and Java Virtual Machine are both platforms.
  • Polymorphism - The ability to call an object that has different data types using the same method name.
  • Primitive Data Type - A primitive data type is a basic variable type that computer itself can understand. In Java char, int, float and double are all primitive data types.
  • Parallel Array - Parallel arrays are used to create create connected lists of data. See Parallel Arrays.
  • prefix - a letter or letters placed before or joined to the beginning of word which affects or changes the meaning of that word.
  • Private - A keyword used in a variable or method declaration. Indicates that the variable or method is only accessible by other elements in its class
  • Programming language - The language that you write code in. In this context, language refers to a set of rules that define the syntax and meanings of words and symbols (like the semicolon). In COMP1010, we learn about the Java programming language.
  • package - a collection of supplied code made available by declaring that you are using it. This is usually code supplied by the creators of Java and is organized around specific tasks. Ex. javax.swing is organized around GUI components.
  • Public - A keyword used in a variable or method declaration. Indicates that the variable or method can be accessed by elements in other classes

- R -

  • Return Value - Any user-declared method can return a primitive data type, such as void, int, String, etc. For example, to return an int from the method calcAvg(), our method declaration is: public static int calcAvg(...).
  • Reference Variable - A variable that is used as a pointer (or an address) to an object. [ABU]

- S -

  • String - A String is an array of characters that Java treats in a special way, allowing you to mainpulate it more easily.
  • Sequential - Sequential refers to doing one thing at a time; in order. An example would be when searching an array, we would check element 0, then element 1, then element 2, ..., element n.
  • Selection Sort - Selection Sort is a sorting algorithm which iterates through an array multiple times and swaps index values based on ascending or descending sort order. See Sorting Arrays.

- T -

  • TextPad - A common Windows based word processor used in programming. TextPad allows for program compilation and execution without using a command prompt.

- U -

  • User - The person who is giving input to and interpreting output from your program.
  • User-Defined Method - A section of code which is declared once in a program, then used by other code sections.

- V -

  • Virtual Machine - A virtual machine is a program that simulates a CPU, allowing implementation of Java on a variety of actual machines independent of their CPU architecture.

- W -

  • While Loop - A while loop is a conditional loop, this kind of loop will loop forever unless a certain condition is met. E.g. Looping through game code (e.g. Tic-Tac-Toe) until there are no more empty spots on the board or there is a winner.
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