Home -> Programming -> Appendices -> Definitions


A step by step solution to a problem which solves the problem in a finite amount of time.
Algorithmic Thinking
The set of thought processes used to create algorithms.
The most common code system for representing language, letters, numbers and punctuation on a computer. It can represent 127 or 255 code states. See also Unicode.
Assignment Statements
A VB command which copies the literal or variable contents from the right side of the equals sign to the variable or property on the left side of the equals sign.
Sizes a Label just large enough to display the contents of the Text property.

Binary Language
An alternate name for machine language.
Bit is an acronym for binary digit. A single bit can take the value of 1 or 0. Naturally one bit on its own is rather limited in what it can represent so bit are normally grouped together four at a time (a Nibble) or eight at a time (a byte).
A data type whose only values are True or False.
A property of Label objects which places a border around the object.
Break Time
A mode of Visual Studio editor during which the program is running but temporarily paused. See also Design Time and Run Time.
A control that allows the user to trigger a subroutine or procedure. The advantage of using a button to allow the user to trigger events is that the button is always visible on the form and therefore easy to see and use. It is about as fast as using a menu, but slower than a keyboard shortcut.

A control used for either input or output to allow the user to select more than one option at the same time.
The property of a CheckBox control which indicates whether the object is selected. Data type is Boolean.
A blueprint or pattern for an object. It contains the variables and the methods of the object.
A method used by Label and TextBox to remove the current contents of the object.
Pressing and releasing the left mouse button. If performed while hovering over a control this triggers an event in the program.
A Visual BASIC operation which causes one specific thing to happen.
Common Dialog Boxes
These are a collection of preprogrammed dialogs which allow the user to perform common tasks such as selecting colors, fonts and accompanying characteristics, printing, opening and saving files.
This is the selection structure based on If .. then. A comparison is made, and if the result is True, an action is performed (Then clause)

Data Type
A specification made when a variable is declared. This determines what type of data can be stored in the variable space.
A numeric data type which uses 16 bytes of memory to hold decimal numbers.
Design Time
A mode of Visual Studio editor during which forms are created, and code is written. See also Break Time and Run Time.
A window (form) which pops up when a program is running, usually to obtain information from the user. It may be modal or non-model
A numeric data type which uses 8 bytes of memory but can hold decimal numbers.

boolean property which determines whether a control responds to user clicks.
A program signal which is generated by a user who interacts with the controls on a form. The event causes the execution of a module of code know as a procedure.
Event Driven
A methodology used by a programming language to link user action to execution of specific sets of program instructions. It causes a program to be broken up into pieces. This is desirable because it increases reliability of the program by keeping component modules shorter and simpler.
Event Procedure
A procedure that is linked to a specific even on a user control. this procedure is thus triggered every time the control is activated.

A unit of information which is normally embedded in a larger collection of information called a record which describes one entity. a field often corresponds to a column.
Fitts Law
A law of human movement (pointing), predicting that the time required to move from a starting position to a final target area, is a function of the distance to the target and the size of the target. Originally put forward by Paul Fitts in 1954.
Forced Choice
The name of the selection structure which forces a program to execute one of two possible sets of instructions. A test is performed and if the result is True, instructions set A is executed while if the result is False, instruction set B is executed.
This is the property which causes the cursor to appear in its control. Although many controls have this property, some of them can not receive a focus. If you send a focus message to such a control, the focus will be passed on to the next control which is permitted to receive focus. This behavior can be used in combinations with access keys to give the user quick access to almost any control on the form.
VB's name for a program's window.
This is the sub which is executed by each form just prior to drawing itself on the screen. Since it is always called just before the form appears, it is an ideal location for any initialization we need to do for our form.
A subroutine which may perform an action but always returns a value at the end of its execution.

Graphical User Interface (GUI)
The term which describes software based on the paradigm researched by Xerox Corporation at their Palo Alto research facility between 1969 and the early 1980's. It was viewed by Apple engineers and became the user interface for the Macintosh computer released in 1984. Microsoft then adapted the same ideas to create the Windows 95 operating system introduced in 1995. It is characterized by placing program content in a Window, using icons as well as text for communicating with users, using drop down menus to allow the user to direct program actions, and pointing devices, initially a mouse, to simplify screen access by the user.
As the name suggests this control provides a box frame to surround other controls effectively grouping those controls. It can also display a text title to indicate the function of the group of controls.

Hick's Law
A law that states that the time to make a decision is inversely proportional to the number of choices.
High Level Languages
These are programming languages which are closer to human language than machine or binary language.

An instance of an object is a variable of our object type. Class is the blueprint, an instance is a house built from that blueprint.
One execution of a loop structure.
The generic programming term for variable, procedure and function names.
Any information which is entered onto a form (window) for the purpose of allowing a program to process it and create program output. Input is entered into the controls placed on the form. Clicking buttons or selecting menu commands is also a form of input since it tells the program what to do next.
Interpreted Language
There are two methods of translating source code into machine language. Compiled programs translate the entire program all at once, and produces an exe file as an output of the process. Interpreted programs are kept as source code and are translated each time they are executed. The translation occurs line by line. Note VB actually is translated into a ?? language which is why the VB framework is required to finish the translation into the program executable.
A variable data type that represents whole numbers only. An integer can be declared as Int16 which occupies 2 bytes, as Int32 which occupies 4 bytes or Int64 which occupies 8 bytes of memory.



A control used to display text on a form. The user can see the text but can not change the text. Thus the control is used for two purposes. First: to display descriptive text on the form to help the user understand the purpose of other controls. Second: to display output to the user. When used for this purpose, it is customary to give the label a border.
A single line of programming text or one programming command. This can actually occupy more than one physical line on the screen when the programmer uses the line continuation character.
Line Continuation Character
When the programmer wants to split a command so it occupies more than one line on the screen, they use the line continuation character at the point where they want the line break to occur. The syntax is space underscore ' _' without the quotes of course. This technique is used to improve code readability.
Term which means we are looking at the actual data rather than a variable which contains the data. Textual data used as a literal must be enclosed in double quotes e.g. "Hello World" while numeric literals are bare e.g. 45.

Machine Language
The language used by computers to direct the machine to perform specific actions. It is composed entirely of 0's and 1's, each of which individually is known as a bit (short for Binary Digit). Bits are normally grouped 8 at a time. this grouping is known as a byte. The pattern of bytes represent numbers, letters and commands which are manipulated by the CPU to cause specific things to happen. There are actually many different dialects, if you will, of machine language. Each Family of CPU speaks its own unique form of machine language.
Menu Strip
The VB control which gives a program a set of menu commands.
Menu Command
This is a control which creates events, like buttons but is hidden into the Menu system and only accessible by clicking the menu bar and moving to the desired command or by using a keyboard shortcut for that menu item if it exists. The advantage of using a menu command is that is preserves space on the form for other uses.
This is a procedure or a function which is declared in, and therefore belongs to an object.
A generic term which refers to a procedure, a function or a method. It is a formal unit of code.

A property of all toolbox controls, this property is one of the essential properties which must be set when a control is first created. Names entered must follow the Naming Convention Rules.
Naming Convention Rules
The rules which a programmer must follow to legally name variables, procedures, functions, forms and classes. The rules are listed here.

A programming construct which encapsulates both data and procedures and functions to create a stand alone code module which is used to perform specific tasks.
Object Oriented
A programming language which is organized by integrating variables and code into units called objects. These objects become the building blocks of object-oriented programs
A display of information on a form designed to inform or communicate with the user. It is accomplished by using controls, dialog boxes and message boxes.

Picture Box
A VB control which can display a graphical image.
Pre-test Loop
A loop in which the test to decide whether to enter or stay in the loop is performed before the set of instructions in the loop is executed.
Post-test Loop
A loop in which the test to decide whether to enter or stay in the loop is performed after the set of instructions in the loop is executed.
A subroutine is a set of instructions which performs an action. These are created to modularize our code. Breaking code into subroutines allows us to link a particular set of instructions to an event which is generated by the user. This is why Visual BASIC is described as an Event-Driven Language. Breaking code into subroutines also makes it easier to find errors in our code and fix them thus improving program maintainability.
This is the term which describes the conversion of input into output.
A set of instructions which produces some particular output or result.


This is a boolean control which is used in a group with other radio buttons. Only one of the group may be selected at a time. Selecting any radio button in the group automatically causes all other buttons in the group to be deselected or set to false.
Readable and Accessible
Readable means that the program is easily read, and accessible is having the code written in such a way that programmer does not have to work as hard to read the code. This is accomplished though using the automatic indentation feature and following certain rules such as capitalizing constants. A capitalized word stands out and gives better accessibility.
A property which causes a textBox control to be viewable but not able to receive input.
A collection of fields which describes an entity. A record is often corresponds to a row.
Run Time
A mode of the Visual Studio editor during which the program is running. See also Break Time and Design Time.

name for the collection of decision making structures used by all programming languages to cause programs to branch as desired.
the order in which commands are executed, it is determined by the order by which they are listed.
A numeric data type which uses 4 bytes of memory but can hold decimal numbers.
A Visual BASIC command which causes one specific thing to happen.
Structured Language
This is a language that requires the programmer to follow certain rules to create a program which is more predictable, easier to understand and easier to maintain.
A set of instructions which govern the programming language. It is analogous to grammar in English.

Awindow pane which allow the user to toggle by tab effectively doubling, tripling etc. the space for controls.
a property which determines the order of movement when the tab key is pressed. Value of 0 always get initial focus.
A data type consisting of numbers, letters, punctuation and special characters.
control used for text input and will also display data entered.
an event which triggers whenever a key is pressed to insert or delete a character from the textBox.
Tool Bar
This adds a toolbar to your form. A toolbar is a substitute for a menu strip or for other larger controls. Its main advantage is its visibility.
Text Files
Files which contain only ASCII or Unicode characters.
Tool Tip
This control, when added to a form, creates an extra property of the same name into which you can enter a text prompt to give the user some extra information as to what a particular control does.

The current system used by most computers for representing language in a computer. It has the advantage over ASCII that it has 65,536 code states and so can be used for languages such as Chinese and Japanese while ASCII can not.
User Interface
The sum of all the tools used to allow the user to interact with the program or operating system of the computer. Currently in Windows we use a Graphical User Interface (GUI) which has also been described as the WIMP interface because its intermediary tools are windows, icons menus and pointers.
User Interface Friction
This is a term proposed by Andreas Pfeiffer. It is the delay which is an inherent part of the User Interface. Among Windows operating systems Windows XP has the least Interface Friction. Windows Vista and Windows 98 have the most. Interface friction is undesirable but all operating systems have some of it. Some have more than others. To date lowest Interface Friction scores are found on Mac OS X systems.

boolean property which determines whether the user can see the control.
Visual BASIC
programming language which is a version of BASIC that uses a GUI editor to speed up creation of modern GUI programs.
A space which is created in memory to temporarily hold data. The space allocated depends on the type of data to be stored in the variable and is determined when the variable is declared.
Variable Declaration
Before using a variable in a program it must be declared. VB allows variable declaration anywhere in a program, but since putting declarations anywhere can make it hard to find them when checking or debugging your programs it is customary to declare them only in specific places. Local variables are customarily declared just after their procedure declaration, while module variables are customarily declared just after the form declaration.

Windows Application
A program written to run under one of the many the Windows Operating Systems. It uses Windows system calls and therefore will not run on any other platform unless special arrangements (e.g. virtualization) have been made.