Visual Basic Chapter 1 (Introduction to programming and Visual Basic)

1.1 Computer Systems: Hardware and Software The major hardware components of a computer are the central processing unit (CPU), main memory, secondary storage devices, input devices, and output devices. Computer programs are stored in machine language, as a series of binary numbers. Main memory holds the instructions for programs that are running and data programs are working with, RAM is usually volatile, used only for temporary storage. The two general categories of software are operating systems and application software. 1.2 Programs and Programming language Although the computer can process only programs that are written in machine language, programmers use languages such as Visual Basic to write programs. They then use a compiler to translate their programs to machine language. Keywords (reserved words), operators, variables, syntax, statements, and comments are some of the programming language elements that you will work with when writing a program. The part of the program that the user interacts with is called the user interface. Modern systems use graphical user interfaces. An object is an item in a program that contains data and has the ability to perform operations. A control is a type of object that usually appears in a program's graphical user interface. There are several types of controls available in Visual Basic. Applications in this chapter contained forms, Label, TextBoxes, Buttons, CheckBoxes, RadioButtons, ListBoxes, ComboBoxes, and scroll bars. The appearance of a screen object, such as a form or other control, is determined by the object's properties. An event-driven program is one that responds to events or actions that take place while the program is running. 1.3 More about Controls and Programming All controls have a name. Programmers manipulate or access a control in a programming statement by referring to the control by its name. When the programmer creates a control in Visual Basic, it automatically receives a default name. Any control whose name appears in a programming statement should have a descriptive, programmer-defined name. Although programmers have a great deal of flexibility in naming controls, they should follow some standard guidelines. 1.4 The Programming ProcessThis section outlines the steps for designing and creating a Visual Basic application.1.5 Visual Studio and Visual Studio Express (the Visual Basic Environment) The Visual Basic environment, which is part of Visual Studio, consists of tools used to build Visual Basic applications. Visual Basic can be used to create many different types of applications.