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Lecture 1 Intro to Java Programming

Lecture 1 Intro to Java Programming. Richard Gesick. CHAPTER TOPICS. What is Programming? Basic Computer Concepts Data Representation Introduction to Programming Languages Introduction to Programming Programming Basics Program Design with Pseudocode Developing a Java Application.

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Lecture 1 Intro to Java Programming

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  1. Lecture 1Intro to Java Programming Richard Gesick

  2. CHAPTER TOPICS • What is Programming? • Basic Computer Concepts • Data Representation • Introduction to Programming Languages • Introduction to Programming • Programming Basics • Program Design with Pseudocode • Developing a Java Application

  3. What is Programming? • Creating an application such as a ticketing kiosk, a game, a restaurant ordering system or another business application. • Programming is a science • Many techniques have been developed for accomplishing basic programming tasks • Software engineering practices insure that the program is correct and maintainable • Programming is also creative • We get to solve problems

  4. Basic Computer Concepts • Hardware • Central Processing Unit • Memory and Storage Devices • Operating Systems • Application Software • Computer Networks and the Internet

  5. Typical Computer Hardware • CPU • executes the instructions of the program • Hard disk and CD-ROM • store instructions and data so program can be loaded into memory and executed • Main memory • stores the program instructions and data while executing • Keyboard and mouse • used for data input • Monitor • used to display output from a program • Other accessories, such as a printer

  6. A Typical Design of a Personal Computer

  7. Central Processing Unit (CPU) • Arithmetic Logic Unit • performs integer arithmetic and logical operations • Floating-point Unit • performs floating-point operations • Hardware registers • store data and memory addresses • Instruction Pointer • keeps track of next instruction to execute • Examples of CPUs: • Intel Pentium ™ dual-core E5400, Oracle Sun SPARC, Hewlett-Packard PA-RISC, IBM POWER processor

  8. CPU Instructions • Move data from one location to another • Perform a calculation • Compare data • Change the sequence of instructions to execute (the flow of control)

  9. CPU Speed • Rated in MHz or GHz • In one clock cycle, a CPU • fetches an instruction from memory, • decodes the instruction, or • executes the instruction • Pipelining allows overlap of operations to improve performance • 3.4-Ghz CPU can execute 3.4 billion instructions per second

  10. Memory or Storage Devices • Memory consists of cells that hold one bit. • A bit's value can be 0 or 1 • A byte is 8 binary digits (bits) • Storage capacity is expressed as: • Kilobytes (1,024 bytes) • Megabytes (1,048,576 bytes) • Gigabytes (1,073,741,824 bytes) • Terabytes ( 1.09951 x 1012 bytes)

  11. Operating System (OS) Software • OS boots when computer is turned on, and runs continuously • Controls the peripheral devices (disks, keyboard, mouse, etc.) • Supports multitasking (multiple programs executing simultaneously) • Allocates memory to each program • Prevents one program from damaging another program • Examples: Microsoft Windows, Linux, MacOS

  12. Application Software • Written to perform specific tasks • Runs "on top of" the operating system • Examples: word processor, spreadsheet, database management system, games, Internet browser, etc.

  13. Computer Networks • Networks connect two or more computers so they can share files or devices • Local Area Network (LAN) • computers located geographically close to one another • Servers provide services • access to database • downloading of files • email delivery • Clients use these services. • Most desktop computers are clients.

  14. The Internet • A network of networks • Evolved from the ARPANET military research project • Web servers deliver Internet content (web pages) to clients via a browser. • Web pages are identified using a URL (Uniform Resource Locator) • Domain Name System (DNS) Servers • translate a URL to an Internet Protocol (IP) address

  15. Data Representation • Binary Numbers • Expressed in base 2 system (two digits are 0 and 1) • Hexadecimal Numbers • Base-16 system used as shorthand for representing binary numbers • The Unicode Character Set • Used to represent characters

  16. Binary Equivalents of Decimal Numbers DecimalBinary Equivalent 0 0000 1 0001 2 0010 3 0011 4 0100 5 0101 6 0100 7 01118 1000

  17. Powers of 2 DecimalDecimal 20 1 28 256 21 2 29 512 22 4 210 1,024 23 8 211 2,048 24 16 212 4,096 25 32 213 8,192 26 64 214 16,384 27 128 215 32,768

  18. Decimal (base 10) numbers A decimal number can be represented as the sum of powers of 10 (the base) with coefficients in the base 10 alphabet (0 - 9) For example: 2485 = 2 * 103 + 4 * 102 + 8 * 101+ 5 * 100 2485 = 2 * 1000 + 4 * 100 + 8 * 10 + 5 * 1 2485 = 2000 + 400 + 80 + 5

  19. Converting From Decimal to Binary Just as a decimal number can be represented as a sum of powers of 10 (the base) with coefficients in the base 10 alphabet (0 to 9) A decimal number can be represented as the sum of powers of 2 (the base of the binary system) with coefficients in the base 2 alphabet (0 and 1) • So we need an algorithm to do that

  20. Converting From Decimal to Binary • Find the largest power of 2 that is smaller than or equal to the decimal number • Subtract that number from the decimal number • Insert 1 in the binary number for the position equivalent to that power of 2 • Repeat 1 - 3, until you reach 0

  21. Example: convert 359 to binary • Largest power of 2 that is smaller than 359 is 256 (28) • 359 - 256 = 103 so 359 = 28 * 1 + 103 • Largest power of 2 that is smaller than 103 is 64 (26) • 103 - 64 = 39 so 359 = 28 * 1 + 26 * 1 + 39 (continued on next slide)

  22. Example: convert 359 to binary • Largest power of 2 that is smaller than 39 is 32 (25) • 39 - 32 = 7 so 359 = 28*1 + 26*1 + 25*1 + 7 • Largest power of 2 that is smaller than 7 is 4 (22) • 7 - 4 = 3 so 359 = 28 * 1 + 26 * 1 + 25 * 1 + 22 * 1 + 3 (continued on next slide)

  23. Example: convert 359 to binary • Largest power of 2 that is smaller than 3 is 2 (21) • 3 - 2 = 1 so 359 = 28 * 1 + 26 * 1 + 25 * 1 + 22 * 1 + 21 * 1 + 1 • Largest power of 2 that is smaller than or equal to 1 is 1 (20) • 1 - 1 = 0, so we are finished

  24. Our Results • Insert a coefficient of 0 for any missing powers of 2 Thus, 359 = 28*1 + 27*0 + 26*1 + 25*1 + 24*0 + 23*0 + 22*1 + 21*1 + 20*1 Removing powers of 2, we get: 1 0 1 1 0 0 1 1 1 or 1 0110 0111

  25. Hexadecimal Numbers • Base-16 number system • Uses digits 0 - 9 and letters A – F • For example: C in hex represents 12 in decimal • One hexadecimal digit can express decimal values from 0 to 15 • Thus, one hexadecimal digit can represent 4 bits

  26. Hexadecimal - Binary Equivalents Hex Binary Hex Binary 0 0000 8 1000 1 0001 9 1001 2 0010 A 1010 3 0011 B 1011 4 0100 C 1100 5 0101 D 1101 6 0110 E 1110 7 0111 F 1111

  27. Examples Binary number: 0001 1010 1111 1001 Hex equivalent: 1 A F 9 Binary number: 1011 0011 1011 1110 Hex equivalent: B 3 B E

  28. The Unicode Character Set • Each character is stored as 16-bits • Maximum number of characters that can be represented: 65,536 (216) • ASCII character set (used by many programming languages) stores each character as 7 bits (maximum number of characters is 128). • For compatibility, first 128 characters of Unicode set represent the ASCII characters

  29. Some Unicode Characters CharacterDecimal ValueHex Value * 42 002A 1 49 0031 2 50 0032 A 65 0041 B 66 0042 a 97 0061 b 98 0062 } 125 007D

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