CS101 Algorithms & Programming I Section 4

1. CS101 Algorithms & Programming I Section 4 CS101 - Algorithms & Programming I

2. Course Information • Instructor: Dr. İlyas Çiçekli Office: EA504 Phone: 290-1589 Email: ilyas@cs.bilkent.edu.tr Office Hours: Thursday 9:30-11:30 CS101 - Algorithms & Programming I

3. Course Organization • Four Sections for CS • Only Computer Engineering Students • Section 4 is taughted by Dr. İlyas Çiçekli • Sections 1, 2 and 3 are taughted by Dr. David Davenport • 4 credits • 3 hr. class time & 4 hr. lab each week • Course Hours: Tuesday 13:40-15:30 Thursday 15:40-17:30 (BZ03) • We are going to have one hour class on Thursdays (most of the time, not at the beginning) • Lab Hours: Wednesday 13:40-17:30 (B201/B202 – BCC Building Second Floor) • Common Exams and Common Grading • All sections have common midterm, final exam and labs CS101 - Algorithms & Programming I

4. Course Organization (Textbook) Absolute Java - Third EditionPearson International EditionWalter Savitch,Pearson Education, 2008. CS101 - Algorithms & Programming I

5. Course Organization (Exams) • One midterm, one final exam. • Dates and times will be announced on the web and in class. • All exams will be closed book and notes --students will only be allowed to take a single A4 crib-sheet into the exam room. • There will be a single makeup exam that may be taken only by those who missed an exam due to documented medical reasons. It will be given in the last week and will include all material. CS101 - Algorithms & Programming I

6. Course Organization (Labs) • All CS101 lab sessions take place in the computer center building (rooms B201 & B202). • Lab Hours: Wednesday 13:40-17:30 (for Section 4) • Attendance is mandatory! CS101 - Algorithms & Programming I

7. Course Organization (Course Web Page) Course Web Page: http://www.cs.bilkent.edu.tr/~david/cs101 • All important announcements, notices, homeworks, lab assignments and sample solutions will be posted on the course homepage • For all sections and general information http://www.cs.bilkent.edu.tr/~ilyas/Courses/CS101 • for Section 4 • Students should consult these pages at least once a week! CS101 - Algorithms & Programming I

8. Course Organization (Grading ) • The midterm examination is 30% • The laboratory is 25%. • The final examination is 35%. • Quizzes and homework assignments are 10% • Some of these marks will be allocated for maintaining Journal quality & for participation in the online Forum. • Common exams and common grading for all sections CS101 - Algorithms & Programming I

9. Course Organization (Syllabus) • Introduction to course • Robo • Algorithms, Structured Design • Computer systems (hardware & software architecture) • Java-- program statements, data, IO & assignment s • Java -- Decision & Repetition  • Java --Methods (static)          • Java -- OOP & using Java's classes and objects   • Java -- Writing classes   • Java -- Collections in Java (ArrayList) • Java -- Arrays CS101 - Algorithms & Programming I

10. Course Organization (Homework for NextWeek) • For labs next week… • Get an A4 fixed page notebook(in addition to your lecture notebook) • Get a floppy disk(or USB memory?) • Get the text book • Read Chapter 1 CS101 - Algorithms & Programming I

11. Computers CS101 - Algorithms & Programming I

12. Computers • A computer is a device capable of performing computations and making logical decisions at very fast speeds. • First electronic digital computer was ENIAC. • built in 1946 at University of Pennsylvania • used to compute ballistic tables • it was very huge • Since from the first computer, computers are getting smaller, but they are getting much powerful. • They are widely used in many areas of society. • banking, scientific research, schools, airplanes, space program, etc. CS101 - Algorithms & Programming I

13. Hardware & Software • The set of instructions controls computers are known as computer programs (software). • programs and data • a program is a series of instructions • The physical structure of the computer is called as hardware. • the physical, tangible parts of a computer • keyboard, monitor, disks, wires, chips, etc. • A computer requires both hardware and software • Each is essentially useless without the other CS101 - Algorithms & Programming I

14. Hardware • A modern computer consists of five main components and they are all parts of computer hardware: • Memory • Central Processing Unit (CPU) • Input Devices • Output Devices • Secondary Storage CS101 - Algorithms & Programming I

15. Main Memory CPU and Main Memory Chip that executes program commands Intel Pentium 4 Sun ultraSPARC III Central Processing Unit Primary storage area for programs and data that are in active use Synonymous with RAM CS101 - Algorithms & Programming I

16. Hard Disk Main Memory Floppy Disk Secondary Memory Devices Information is moved between main memory and secondary memory as needed Secondary memory devices provide long-term storage Central Processing Unit Hard disks Floppy disks ZIP disks Writable CDs Writable DVDs Tapes CS101 - Algorithms & Programming I

17. Monitor Keyboard Hard Disk Main Memory Floppy Disk Input / Output Devices I/O devices facilitate user interaction Central Processing Unit Monitor screen Keyboard Mouse Joystick Bar code scanner Touch screen CS101 - Algorithms & Programming I

18. Computer Organization (Memory) Memory • Store information (data + instructions) • A sequence of memory cells. • a byte is 8 bits • a bit is smallest unit (0 or 1) • Store, retrieve, update • changing pattern of 0 and 1s in memory cells • copying these patterns into some internal registers • Stored information in memory is volatile. • Size of a memory of a typical PC system: 512MB, 1GB, 2GB • KB, MG, GB CS101 - Algorithms & Programming I

19. Computer Organization (CPU) CPU (Central Processing Unit) • Process and manipulate information stored in memory. • It can be divided into two units: CU (Control Unit) and ALU (Arithmetic Logic Unit) • CU coordinates activities of the computer and controls other devices of computer. • ALU processes arithmetic and logical instructions. CS101 - Algorithms & Programming I

20. Computer Organization (Input and Output Devices) Input and Output Devices • Provide the interface between the user and the computer. • Input devices are used to enter instructions or data by the user. • Output devices are used to give results of computations. • Input Devices: keyboard, mouse • Output Devices: monitor, printer CS101 - Algorithms & Programming I

21. Computer Organization (Secondary Storage) Secondary Storage • Computers have limited main memory and information stored in main memory is volatile. i.e. when a computer is switched off, information in its main memory disappears. • There are additional data storage unit, called secondary storage units. • Data stored in these secondary storage units are permanent, i.e. data does not disappear when you switch off the computer. • Some secondary storage units: • Floppy Disks • Hard Disks • Tape Drive • Optic Disk (CD Drive, DVD Drive) • Flash Disk (USB Disks) CS101 - Algorithms & Programming I

22. SOFTWARE • Operating System • Controls all machine activities • Provides the user interface to the computer. • manages resources such as CPU and memory • Widows 95, Widows 98, Solaris, Unix • Application Program • generic form for all other kind of software • games, word processors, compilers • Most operating systems and application programs have a graphical user interface (GUI) • Windows XP • an operating system • uses a graphical user interface. • consists of windows • you point the mouse and click there, you start a program CS101 - Algorithms & Programming I

23. File/Directory • File contains a document and Directory contains files or other directories. • You will be able to create files and directories • a file can contain different types of information, and normally the extension of that file reflects the content of that file. • .doc : a word document • .java : a java program • .class : a class file • .html : a hypertext file used to represent a web page CS101 - Algorithms & Programming I

24. A Computer Specification • Consider the following specification for a personal computer: • 2.8 GHz Pentium 4 Processor • 512 MB RAM • 80 GB Hard Disk • 48x CD-RW / DVD-ROM Combo Drive • 17” Video Display with 1280 x 1024 resolution • 56 Kb/s Modem • What does it all mean?

25. 9278 9279 9280 9281 9282 9283 9284 9285 9286 Main memory is divided into many memory locations (or cells) Each memory cell has a numeric address, which uniquely identifies it Memory

26. Each memory cell stores a set number of bits (usually 8 bits, or one byte) Large values are stored in consecutive memory locations Storing Information 9278 9279 9280 9281 9282 9283 9284 9285 9286 10011010

27. Storage Capacity • Every memory device has a storage capacity, indicating the number of bytes it can hold • Capacities are expressed in various units: Unit Symbol Number of Bytes KB 210 = 1024 kilobyte megabyte gigabyte terabyte MB 220 (over 1 million) GB 230 (over 1 billion) TB 240 (over 1 trillion)

28. Memory • Main memory is volatile - stored information is lost if the electric power is removed • Secondary memory devices are nonvolatile • Main memory and disks are direct access devices - information can be reached directly • The terms direct access and random access often are used interchangeably • A magnetic tape is a sequential access device since its data is arranged in a linear order - you must get by the intervening data in order to access other information

29. RAM vs. ROM • RAM - Random Access Memory (direct access) • ROM - Read-Only Memory • The terms RAM and main memory are basically interchangeable • ROM could be a set of memory chips, or a separate device, such as a CD ROM • Both RAM and ROM are random (direct) access devices! • RAM probably should be called Read-Write Memory

30. Compact Discs • A CD-ROM is portable read-only memory • A microscopic pit on a CD represents a binary 1 and a smooth area represents a binary 0 • A low-intensity laser reflects strongly from a smooth area and weakly from a pit • A CD-Recordable (CD-R) drive can be used to write information to a CD once • A CD-Rewritable (CD-RW) can be erased and reused • The speed of a CD drive indicates how fast (max) it can read and write information to a CD CS101 - Algorithms & Programming I

31. DVDs • A DVD is the same size as a CD, but can store much more information • The format of a DVD stores more bits per square inch • A CD can store 650 MB, while a standard DVD can store 4.7 GB • A double sided DVD can store 9.4 GB • Other advanced techniques can bring the capacity up to 17.0 GB • Like CDs, there are DVD-R and DVD-RW discs CS101 - Algorithms & Programming I

32. Retrieve an instruction from main memory fetch execute decode Carry out the instruction Determine what the instruction is The Central Processing Unit • A CPU is on a chip called a microprocessor • It continuously follows the fetch-decode-execute cycle: CS101 - Algorithms & Programming I

33. The Central Processing Unit • The CPU contains: Performs calculations and makes decisions Arithmetic / Logic Unit Coordinates processing steps Control Unit Small storage areas Registers

34. The Central Processing Unit • The speed of a CPU is controlled by the system clock • The system clock generates an electronic pulse at regular intervals • The pulses coordinate the activities of the CPU • The speed is usually measured in gigahertz (GHz)

35. Monitor • The size of a monitor (17") is measured diagonally, like a television screen • Most monitors these days have multimedia capabilities: text, graphics, video, etc. • A monitor has a certain maximum resolution , indicating the number of picture elements, called pixels, that it can display (such as 1280 by 1024) • High resolution (more pixels) produces sharper pictures

36. Modem • Data transfer devices allow information to be sent and received between computers • Many computers include a modulator-demodulator or modem, which allows information to be moved across a telephone line • A data transfer device has a maximum data transfer rate • A modem, for instance, may have a data transfer rate of 56,000 bits per second (bps)

37. Networks • A network is two or more computers that are connected so that data and resources can be shared • Most computers are connected to some kind of network • Each computer has its own network address, which uniquely identifies it among the others • A file server is a network computer dedicated to storing programs and data that are shared among network users

38. Network Connections • Each computer in a network could be directly connected to every other computer in the network • These are called point-to-point connections Adding a computer requires a new communication line for each computer already in the network This technique is not practical for more than a few close machines CS101 - Algorithms & Programming I

39. Network Connections • Most networks share a single communication line • Adding a new computer to the network is relatively easy Network traffic must take turns using the line, which introduces delays Often information is broken down in parts, called packets, which are sent to the receiving machine and then reassembled

40. LAN Local-Area Networks A Local-Area Network (LAN) covers a small distance and a small number of computers A LAN often connects the machines in a single room or building

41. LAN LAN Wide-Area Networks A Wide-Area Network (WAN) connects two or more LANs, often over long distances A LAN usually is owned by one organization, but a WAN often connects groups in different countries

42. The Internet • The Internet is a WAN which spans the entire planet • The word Internet comes from the term internetworking • It started as a United States government project, sponsored by the Advanced Research Projects Agency (ARPA) - originally it was called the ARPANET • The Internet grew quickly throughout the 1980s and 90s

43. TCP/IP • A protocol is a set of rules that determine how things communicate with each other • The software which manages Internet communication follows a suite of protocols called TCP/IP • The Internet Protocol (IP) determines the format of the information as it is transferred • The Transmission Control Protocol (TCP) dictates how messages are reassembled and handles lost information

44. IP and Internet Addresses • Each computer on the Internet has a unique IP address, such as: 204.192.116.2 • Most computers also have a unique Internet name, which also is referred to as an Internet address: spencer.villanova.edu kant.gestalt-llc.com • The first part indicates a particular computer (spencer) • The rest is the domain name, indicating the organization (villanova.edu)

45. Domain Names • The last part of a domain name, called a top-level domain (TLD), indicates the type of organization: - educational institution edu com org net - commercial entity - non-profit organization - network-based organization Sometimes the suffix indicates the country: New TLDs have recently been added: biz, info, tv, name - United Kingdom uk au ca se - Australia - Canada - Sweden

46. Domain Names • A domain name can have several parts • Unique domain names mean that multiple sites can have individual computers with the same local name • When used, an Internet address is translated to an IP address by software called the Domain Name System (DNS) • There is no one-to-one correspondence between the sections of an IP address and the sections of an Internet address

47. The World Wide Web • The World Wide Web allows many different types of information to be accessed using a common interface • A browser is a program which accesses and presents information • text, graphics, video, sound, audio, executable programs • A Web document usually contains links to other Web documents, creating a hypermedia environment • The term Web comes from the fact that information is not organized in a linear fashion

48. The World Wide Web • Web documents are often defined using the HyperText Markup Language (HTML) • Information on the Web is found using a Uniform Resource Locator (URL): http://www.lycos.com http://www.villanova.edu/webinfo/domains.html ftp://java.sun.com/applets/animation.zip • A URL indicates a protocol (http), a domain, and possibly specific documents

49. Software • The set of instructions controls computers are known as computer programs (software). • a software is a series of instructions • In this course, we will how to write computer programs using Java programming language. • Before, we start to learn Java programming language we will talk about: • ROBO: a simplified program development environment • ALGORİTHMS: a sequence of instructions to solve a problem CS101 - Algorithms & Programming I