1. Chapter 1: An Overview of Computers and Programming Languages J ava P rogramming: From Problem Analysis to Program Design, From Problem Analysis to Program Design, Second Edition Second Edition

2. Java Programming: From Problem Analysis to Program Design, Second Edition2 Chapter Objectives  Learn about different types of computers.  Explore the hardware and software components of a computer system.  Learn about the language of a computer.  Learn about the evolution of programming languages.  Examine high-level programming languages.  Discover what a compiler is and what it does.

3. Java Programming: From Problem Analysis to Program Design, Second Edition3 Chapter Objectives  Examine a Java program.  Examine how a Java program is processed.  Become aware of the Internet and World Wide Web.  Learn what an algorithm is and explore problem- solving techniques.  Become aware of structured and object-oriented programming design methodologies.

4. Java Programming: From Problem Analysis to Program Design, Second Edition4 Introduction  Computers have greatly affected our daily lives— helping us complete many tasks.  Computer programs (software) are designed specifically for each task.  Software is created with programming languages.  Java is an example of a programming language.

5. Java Programming: From Problem Analysis to Program Design, Second Edition5 An Overview of the History of Computers  1950s: Very large devices available to a select few.  1960s: Large corporations owned computers.  1970s: Computers got smaller and cheaper.  1990s: Computers got cheaper and faster and were found in most homes.

6. Java Programming: From Problem Analysis to Program Design, Second Edition6 Elements of a Computer System A computer has two components:  Hardware  Software

7. Java Programming: From Problem Analysis to Program Design, Second Edition7 Hardware Components of a Computer  Central processing unit (CPU)  Main memory

8. Java Programming: From Problem Analysis to Program Design, Second Edition8 Central Processing Unit  Control unit (CU)  Arithmetic logic unit (ALU)  Program counter (PC)  Instruction register (IR)

9. Java Programming: From Problem Analysis to Program Design, Second Edition9 Hardware Components of a Computer

10. Java Programming: From Problem Analysis to Program Design, Second Edition10 Main Memory  Ordered sequence of cells (memory cells).  Directly connected to CPU.  All programs must be brought into main memory before execution.  When power is turned off, everything in main memory is lost.

11. Java Programming: From Problem Analysis to Program Design, Second Edition11 Main Memory with 100 Storage Cells

12. Java Programming: From Problem Analysis to Program Design, Second Edition12 Secondary Storage  Provides permanent storage for information.  Examples of secondary storage:  Hard disks  Floppy disks  Zip disks  CD-ROMs  Tapes

13. Java Programming: From Problem Analysis to Program Design, Second Edition13 Input Devices  Devices that feed data and computer programs into computers.  Examples:  Keyboard  Mouse  Secondary storage

14. Java Programming: From Problem Analysis to Program Design, Second Edition14 Output Devices  Devices that the computer uses to display results.  Examples:  Printer  Monitor  Secondary storage

15. Java Programming: From Problem Analysis to Program Design, Second Edition15 Software  Software consists of programs written to perform specific tasks.  Two types of programs:  System programs  Application programs

16. Java Programming: From Problem Analysis to Program Design, Second Edition16 System Programs  System programs control the computer.  The operating system is first to load when you turn on a computer.

17. Java Programming: From Problem Analysis to Program Design, Second Edition17 Operating System (OS)  The OS monitors the overall activity of the computer and provides services.  Example services:  Memory management  Input/output  Activities  Storage management

18. Java Programming: From Problem Analysis to Program Design, Second Edition18 Application Programs  Written using programming languages.  Perform a specific task.  Run by the OS.  Example programs:  Word processors  Spreadsheets  Games

19. Java Programming: From Problem Analysis to Program Design, Second Edition19 Language of a Computer  Machine language is the most basic language of a computer.  A sequence of 0s and 1s.  Every computer directly understands its own machine language.  A bit is a binary digit, 0 or 1.  A byte is a sequence of eight bits.

20. Java Programming: From Problem Analysis to Program Design, Second Edition20 Language of a Computer

21. Java Programming: From Problem Analysis to Program Design, Second Edition21 Evolution of Programming Languages  Early computers programmed in machine language.  Assembly languages were developed to make programmer’s job easier.  In assembly language, an instruction is an easy-to- remember form called a mnemonic.  Assembler: Translates assembly language instructions into machine language.

22. Java Programming: From Problem Analysis to Program Design, Second Edition22 Instructions in Assembly and Machine Languages

23. Java Programming: From Problem Analysis to Program Design, Second Edition23 Evolution of Programming Languages  High-level languages make programming easier.  Closer to spoken languages.  Examples:  Basic  FORTRAN  COBOL  C/C++  Java

24. Java Programming: From Problem Analysis to Program Design, Second Edition24 Evolution of Programming Languages To run a Java program: 1.Java instructions need to be translated into an intermediate language called bytecode. 2.The bytecode is interpreted into a particular machine language.

25. Java Programming: From Problem Analysis to Program Design, Second Edition25 Evolution of Programming Languages  Compiler: A program that translates a program written in a high-level language into the equivalent machine language.  (In the case of Java, this machine language is the bytecode.)  Java Virtual Machine (JVM): A hypothetical computer developed to make Java programs machine independent.

26. Java Programming: From Problem Analysis to Program Design, Second Edition26 A Java Program public class ASimpleJavaProgram { public static void main(String[] args) { System.out.println("My first Java program."); System.out.println("The sum of 2 and 3 = " + 5); System.out.println("7 + 8 = " + (7 + 8)); } Sample Run: My first Java program. The sum of 2 and 3 = 5 7 + 8 = 15

27. Java Programming: From Problem Analysis to Program Design, Second Edition27 Processing a Java Program  Two types of Java programs are applications and applets.  Source program: Written in a high-level language.  Loader: Transfers the compiled code (bytecode) into main memory.  Interpreter: Reads and translates each bytecode instruction into machine language and then executes it.

28. Java Programming: From Problem Analysis to Program Design, Second Edition28 Processing a Java Program

29. Java Programming: From Problem Analysis to Program Design, Second Edition29 Problem-Analysis-Coding- Execution Cycle  Algorithm: A step-by-step, problem-solving process in which a solution is arrived at in a finite amount of time.

30. Java Programming: From Problem Analysis to Program Design, Second Edition30 Problem-Solving Process 1.Analyze the problem: Outline solution requirements and design an algorithm. 2.Implement the algorithm in a programming language (Java) and verify that the algorithm works. 3.Maintain the program: Use and modify if the problem domain changes.

31. Java Programming: From Problem Analysis to Program Design, Second Edition31 Problem-Solving Process Example: Find the perimeter and area of a rectangle. 1.Get the length of the rectangle. 2. Get the width of the rectangle. 3.Find the perimeter using the equation: Perimeter = 2 * (length + width) 4.Find the area using the equation: Area = length * width

32. Java Programming: From Problem Analysis to Program Design, Second Edition32 Problem-Analysis-Coding-Execution Cycle

33. Java Programming: From Problem Analysis to Program Design, Second Edition33 Programming Methodologies Two basic approaches to programming design:  Structured design  Object-oriented design

34. Java Programming: From Problem Analysis to Program Design, Second Edition34 Structured Design 1.A problem is divided into smaller sub-problems. 2.Each sub-problem is solved. 3.The solutions of all sub-problems are combined to solve the problem.

35. Java Programming: From Problem Analysis to Program Design, Second Edition35 Object-Oriented Design (OOD)  In OOD, a program is a collection of interacting objects.  An object consists of data and operations.  Steps in OOD: 1.Identify objects. 2.Form the basis of the solution. 3.Determine how these objects interact.

36. Java Programming: From Problem Analysis to Program Design, Second Edition36 Object-Oriented Design (OOD) Write a program to automate the video rental process for a local video store. Two objects : the video and the customer. Data with video object: movie name,starring actors,# of copies in stock. Operations on the video object: reducing the number of copies in stock. So each object consist of data and operations on those data

37. Java Programming: From Problem Analysis to Program Design, Second Edition37 Chapter Summary  A computer system is made up of hardware and software components.  Computers understand machine language; it is easiest for programmers to write in high-level languages.  A compiler translates high-level language into machine language.  The Java steps required to execute a program are edit, compile, load, and execute.

38. Java Programming: From Problem Analysis to Program Design, Second Edition38 Chapter Summary  An algorithm is a step-by-step, problem-solving process in which a solution is arrived at in a finite amount of time.  The three steps of the problem-solving process are analyze the problem and design an algorithm, implement the algorithm in a programming language, and maintain the program.  The two basic approaches to programming design are structured design and object-oriented design.