Advanced Painter Application Introducing Computers, the Internet and Visual Basic

1. 1 • Advanced PainterApplication • Introducing Computers, theInternet and Visual Basic

2. Outline • 1.1What Is a Computer? • 1.2 Computer Organization • 1.3 Machine Languages, Assembly Languagesand High-Level Languages • 1.4 Visual Basic • 1.5 Other High-Level Languages • 1.6 Structured Programming

3. Outline • 1.7 Key Software Trend: Object Technology • 1.8 The Internet and the World Wide Web • 1.9 Introduction to Microsoft .NET • 1.10 Test-Driving the Visual Basic Advanced Painter Application

4. In this tutorial you will learn: Identify the characteristics of low-level andhigh-level programming languages. Apply the basics of object-oriented programming. Run your first Visual Basic application. Locate additional .NET and Visual Basic information. Objectives

5. Introduction • Computer use is increasing in almost every field. • In an era of rising costs, computing costs are actually decreasing dramatically because of rapid developments in both hardware and software technology. • Silicon-chip technology has made computing economical and popular in business, industry, government and our personal lives.

6. 1.1 What Is a Computer? • A computeris a device that can perform calculations and make logical decisions much faster than humans can. • Computers process data,using sets of instructions called computer programs. • These programs guide computers through orderly sets of actions that are specified by people known as computer programmers.

7. 1.1 What Is a Computer? (Cont.) • A computer is composed of various devicesknown as hardware: • keyboard • screen • mouse • hard drives • memory • DVD drives • printer • processing units • The programs that run on a computer are referred to as software.

8. 1.2 Computer Organization Computers can be thought of as being dividedinto six units: • Input unit: This “receiving” section of the computer obtains information from input devices. • Input can come from devices such as the keyboard and the mouse. • Output unit: This “shipping” section of the computer takes information that the computer has processed and places it on various output devices. • Output can be displayed on screens, printed on paper, played on audio/video devices, and transmitted over the Internet.

9. 1.2 Computer Organization (Cont.) • Memory unit: This “warehouse” section of the computer stores data while an application is running. Its information is immediately available for processing. • To be executed, computer programs must be in memory. • The memory unit retains information until it can be sent to output devices. • Often, the memory unit is called either memoryorprimary memory. • Random-access memory (RAM) is an example of primary memory. • Primary memory is usually volatile, which means that it is erased when the machine is powered off.

10. 1.2 Computer Organization (Cont.) • Central processing unit (CPU): The CPU supervises the operation of the other sections. • Arithmetic and logic unit (ALU): The ALU (a part of the CPU) performs calculations and makes decisions. • Secondary storage unit: This unit is the “warehousing” section of the computer. • Devices such as hard drives, CD-ROM drives, DVD drives, and USB memory sticks are secondary storage units. • These normally hold programs or data that other units are not actively being used. • The computer can retrieve this information when it is needed later in time. Secondary storage is nonvolatile. • Information in secondary storage takes much longer to access than information in primary memory.

11. 1.3 Machine Languages, Assembly Languagesand High-Level Languages • Programmers write instructions in programming languages. Some of these are directlyunderstandable by computers, and others require intermediate translation steps. • Computer languages that are in use today can be divided into three general types: • machine languages • assembly languages • high-level languages

12. 1.3 Machine Languages, Assembly Languagesand High-Level Languages (Cont.) • A computer can directly understand only its own machine language. • As the “natural language” of a particular computer, machine language is defined by the computer’s hardware design. Machine languages are machine dependent. • Machine languages generally consist of streams of numbers (ultimately reduced to 1s and 0s in the binary number system).

13. 1.3 Machine Languages, Assembly Languagesand High-Level Languages (Cont.) • The following section of a machine-language program demonstrates the incomprehensibility of machine language to humans: +1300042774+1400593419+1200274027 • Machine-language programming proved to be slow and error prone.

14. 1.3 Machine Languages, Assembly Languagesand High-Level Languages (Cont.) • Programmers began using English-like abbreviations to represent the computer’s basic operations. • These abbreviations formed the basis of assembly languages.LOAD BASEPAYADD OVERPAYSTORE GROSSPAY

15. 1.3 Machine Languages, Assembly Languagesand High-Level Languages (Cont.) • Translator programs called assemblers convert assembly-language programs to machine language. • Although it is clearer to humans, computers cannot understand assembly-language code until it is translated into machine language. • Assembly languages still require many instructions to accomplish even the simplest tasks.

16. 1.3 Machine Languages, Assembly Languagesand High-Level Languages (Cont.) • To speed up the programming process,high-level languages were developed. • Programs called compilers convert high-level-language programs into machine language. • High-level languages look almost like everyday English and contain common mathematical notations. grossPay = basePay + overTimePay • Visual Basic is one of the world’s most popularhigh-level programming languages.

17. 1.4 Visual Basic • Visual Basic evolved from BASIC (Beginner’s All-purpose Symbolic Instruction Code), which was developed as a language for writing simple programs quickly and easily. • When Bill Gates founded Microsoft Corporation in the 1970s, he implemented BASIC on several early personal computers.

18. 1.4 Visual Basic (Cont.) • In the late 1980s and the early 1990s, Microsoft developed the Microsoft® Windows®graphical user interface (GUI). • Visual Basic was introduced by Microsoft in 1991 to make programming Windows applications easier.

19. 1.4 Visual Basic (Cont.) • Visual Basic is a so-called object-oriented,event-driven visual programming language. • Programs are created with the use of a softwaretool called an Integrated Development Environment (IDE). • The latest versions of Visual Basic are fully object oriented and respond to user-initiated events such as mouse clicks, keystrokes and timers. • In Visual Studio, it is convenient to make programs by dragging and dropping predefined objects like buttons and textboxes.

20. 1.4 Visual Basic (Cont.) • Microsoft introduced its .NET strategy in 2000. • The .NETplatform allows applications to be distributed to a variety of devices. • Software components created in different .NET programming languages can communicate with one another.

21. 1.5 Other High-Level Languages • Although hundreds of high-level languages have been developed, only a few have achieved broad acceptance. • IBM Corporation developed Fortran in themid-1950s to create scientific and engineering applications. • COBOL was developed in the late 1950s by a group of computer manufacturers. COBOL is used primarily for business applications that require the manipulation of large amounts of data.

22. 1.5 Other High-Level Languages (Cont.) • The C language gained widespread recognition asa development language for the UNIX operating system. • C++ was developed by Bjarne Stroustrup in the early 1980s at Bell Laboratories. C++ provides capabilities for object-oriented programming (OOP). • Objects are reusable software components that model items in the real world. • Object-oriented programs are easier to understand, correct and modify.

23. 1.5 Other High-Level Languages (Cont.) • Developers use Java to create web pages with dynamic content, to build large-scale enterprise applications, to enhance the functionality of web servers, and to provide applications for consumer devices. • In 2000, Microsoft announced C#. The C# programming language was designed specifically for the .NET platform. Like Visual Basic, C# is object oriented and has access to .NET’s library.

24. 1.6 Structured Programming • During the 1960s, software-development efforts often ran behind schedule, costs greatly exceeded budgets and the finished products were unreliable. • Research activity intended to address these issues resulted in the evolution of structured programming. • Pascal was designed for teaching structured programming, but lacks many features needed to make it useful in commercial, industrial and government applications. • The Ada programming language, based on Pascal, was developed under the sponsorship of the U.S. Department of Defense (DOD) during the 1970s and early 1980s.

25. 1.7 Key Software Trend: Object Technology • Object technology is a packaging scheme for creating meaningful software units. • Almost any noun can be reasonably represented as a software object. • Objects: • have properties such as color, size and weight • perform actions such as moving, sleeping or drawing • A class specifies the general format of its objects, and the properties and actions available to an object depend on its class.

26. 1.7 Key Software Trend: Object Technology (Cont.) • Procedural programming languages focused on actions (verbs) rather than objects (nouns). • Object-oriented languages more naturally reflects the way in which we perceive the world. • This has resulted in significant productivity gains. • Properly designed classes can be reused on future projects • Using libraries of classes reduces the amount of effort required to implement new systems • The production of software is more understandable because it is better organized and has fewer maintenance requirements.

27. 1.7 Key Software Trend: Object Technology (Cont.) • Instead of worrying about the details of how objects are implemented, you can focus on the behaviors and interactions of objects. • Visual Basic is one of the world’s most widely used object-oriented languages.

28. 1.8 The Internet and the World Wide Web • In the late 1960s, ARPA rolled out plans to network the main computer systems of ARPA-funded universities and research institutions. • This became known as the ARPAnet, the grandparent of today’s Internet. • Its main benefit proved to be the capability for quick and easy communication via what came to be known as electronic mail (e-mail).

29. 1.8 The Internet and the World Wide Web (Cont.) • The protocol for communicating over the ARPAnet became known as the Transmission Control Protocol (TCP). • TCP ensured that messages, consisting of pieces called “packets,” were properly routed from sender to receiver, arrived intact and were assembled in the correct order. • One challenge was to enable different networks to communicate with each other. • ARPA accomplished this by developing theInternet Protocol (IP), which created the current architecture of the Internet. • The combined set of protocols is now called TCP/IP.

30. 1.8 The Internet and the World Wide Web (Cont.) • Companies started to develop and enhance their Internet presence. • This generated fierce competition among communications carriers and hardware and software suppliers. • As a result, bandwidth has increased tremendously, while hardware costs have plummeted.

31. 1.8 The Internet and the World Wide Web (Cont.) • The World Wide Web is a collection of hardware and software associated with the Internet. • In 1989, Tim Berners-Lee of CERN began to develop a technology for sharing information via “hyperlinked” text documents called HyperText Markup Language (HTML). • He also wrote communication protocols such as HyperText Transfer Protocol (HTTP). • In October 1994, Berners-Lee founded the World Wide Web Consortium, devoted to developing technologies for the World Wide Web.

32. 1.8 The Internet and the World Wide Web (Cont.) • The Internet and the web will surely be listed among the most important creations of humankind. • Today’s applications can be written to communicate among the world’s computers. This is the focus of Microsoft’s .NET strategy. • The Internet and the World Wide Web: • make information instantly and conveniently accessible, • and allow individuals and small businesses to achieve worldwide exposure.

33. 1.9 Introduction to Microsoft .NET • In June 2000, Microsoft announced its.NET initiative • The .NET initiative permits developers to create applications in any .NET-compatible language. • Part of the initiative includes Microsoft’s ASP.NET. • The .NET strategy extends the idea of software reuse to the Internet. • Visual programming enables .NET programmers to create applications using prepackaged graphical components.

34. 1.9 Introduction to Microsoft .NET (Cont.) • The Microsoft .NET Framework: • executes applications and web services • contains a class library (called the Framework Class Library) • and provides many other programming capabilities.

35. Test-Driving the AdvancedPainter Application • Open a Windows Explorer window and navigate to the C:\Examples\Tutorial01 directory (Fig. 1.1). Double click this file torun the application Figure 1.1|Contents of C:\Examples\Tutorial01.

36. Test-Driving the Advanced Painter Application (Cont.) • Double-click the file name AdvancedPainter.exe to run the application (Fig. 1.2). RadioButtons GroupBoxes Panel Buttons Figure 1.2|Visual Basic Advanced Painter application.

37. Test-Driving the Advanced Painter Application (Cont.) • Select a small red brush, and begin to draw a flower (Fig. 1.3). Figure 1.3| Drawing with a new brush color.

38. Test-Driving the Advanced Painter Application (Cont.) • Select a large green brush and continue drawing (Fig. 1.4). Figure 1.4| Drawing with a new brush size.

39. Test-Driving the Advanced Painter Application (Cont.) • Select a medium blue brush and draw rain drops (Fig. 1.5). Close box Figure 1.5| Finishing the drawing.