Учебное пособие состоит из двух частей и англо-русского словаря. Материалом для пособия послужило американское издание для изучающих компьютер P. Norton "Introduction to Computers"
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| UNIT 6. Programming
Visual Programming The object-oriented, event-driven environment of modern programming has changed how information flows through a program. It has given the control of a program's actions to the user. In the past, programmers created program-centered processing, in which the flow of action was dictated totally by the program. Even in an interactive program, where information flowed in two directions, the central focus was always the program with its preset logic and processing path. Object-oriented, event-driven programming has changed the programming environment by putting the user in control. The user now chooses which actions are used, chooses how each action is started, and directs the flow of the entire activity. As a result, the programmer cannot presume which objects the user will choose or the order in which they will be chosen. Event-driven programs are designed around the interface options available to the user. An event is initiated by the user. When the user clicks an icon with the mouse, presses the Enter key, or moves the pointer on the screen, an event occurs. Each event causes an object to gather its data, structure it, and process it. Event-driven programs are created in a visual WYSIWYG environment that uses a visual programming language (VPL). A VPL allows the programmer to create visually the graphical images the user will see and use. The programmer combines graphical icons, forms, diagrams, and expressions to create two-or three-dimensional programs to run in a graphical user environment. Some of the most commonly used visual languages are Prograph CPX for the Apple Macintosh, Microsoft's Visual Basic, and Visual C++ for the Windows environment. Visual programs for Java and scripting environments – JavaScript and VBScript – have recently emerged. These languages use graphical objects, such as icons, forms, or diagrams, to create programs that run in a visual environment. Programming in a visual language involves placing controls in the graphical presentation so that users can interact with them. Controls are the various tools through which the user can enter data, begin a process, or indicate a choice. The Open dialog box (found in nearly all Windows-based programs), for example, is filled with various types of controls, such as buttons, lists, text boxes, and more. Placing controls on a graphical environment typically is done using the drag-and-drop technique. The programmer chooses the control to be made available to the user for an event and places it on the window form. Usually, the available controls are contained in a menu, list, or dialog box for the programmer's ease of access and use, as in the Visual Basic toolbox. Visual programming is much easier for the programmer because it is based on how a programmer (and the user) sees items on the screen rather than on the structure of the program. As in many other areas of computer software, the visual interface is making highly complex functions accessible to the everyday user. жүктеу/скачать 0,7 Mb. Достарыңызбен бөлісу:
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