Computer Science. ESC 120 Introduction to Engineering Design

Transcription

1 Computer Science ESC 120 Introduction to Engineering Design Dr. Sunnie Chung Dept. of Electrical Engineering and Computer Science Cleveland State University

2 What is Engineering? Application of Scientific and Mathematical Knowledge to Design and Buildstructures, machines, devices, systems, materials and processes, and Services.

3 Engineering vs. Science Science: To know To understand and describe the nature E.g., Planetary system: movement and interaction of Sun, Earth, and Moon Engineering: To create Create new things within what nature allows us E.g., Communication satellites, Web Services

4 What is Computer Engineering Computer Engineering Design and Analyze digital hardwareand software systems Involve Computers Systems that contain computers

5 What is Computer Science? Computer Science is Study of Computer Software Study of Software Design and BuildSoftware Systems (Programs) to Create Computing Systems, Services, or any Innovations Involve Computers Systems that contain computers or can be connected to computers

6 What is Software Systems? Programsthat build Computing Systems, Services, Applications, or any Creations that are written in Computer Programming Languages Examples of Software Systems: Services: Online Library Systems, Amazon Web Services, CSU CampusNet Google Search Systems: Google Search, Google Map Social Network Systems: Facebook, Twitter, LinkedIn Innovation: IPhone, Mobil Phone Apps Computer Applications: Computer Games

7 Computer systems based on its usage General-purpose computer system by Computer Science, Software Engineering The computer is the end-product It allow users to load their own programs do various tasks It can run any number of software applications Special-purpose computer system Computer Engineering (Embedded computer system) The computer is part of a larger system

8 Embedded Computer System Computer integrated (i.e., embedded) within other system The computer performs a specific function The computer may not be visible and its program cannotbe altered by users Complexity of computer varies significantly; e.g., Microwave oven Digital camera Airplane navigation control

9 General Purpose Computers Any Types of general-purpose Computer Systems User Created Applications are infinite Required Software Systemsthat are complex and multilayered structure Smart phone Tablet/Laptop Desktop computer Server Super computer

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11 A General Purposed Computer System Hardware : CPU (Intel Processor), Memory (RAM), Hard Disk, Monitor, Printer Software: Developed by Computer Science or Software Engineering Programs that written in a programming language to perform specific tasks

12 Software Systems Programsthat build Computing Systems, Services, Applications, or any Creations that are written in Computer Programming Languages Examples of Software Systems: Services: Online Library Systems, Amazon Web Services, CSU CampusNet Google Search Systems: Google Search, Google Map Social Network Systems: Facebook, Twitter, LinkedIn Innovation: IPhone, Smart Phone Apps Computer Applications: Computer Games

13 Search Engine Systems : Google Map

14 Social Network System: Facebook

15 Web Service System : Class Search of CSU CampusNet

16 Amazon Webserver

17 Database System

18 Mobile Phone, Tablet Applications

19 Computer Graphics: CGI in Movie

20 What are the Jobs in Computer Science Programmers Software Engineers System Programmers System Administrators Test Engineers Software Developers Web Designer Web Developers Database Administrators Database Developers System Architects Software Architects Data Analysts Data Scientists Computer Scientists

21 Brief History of Computers Hardware of Computers

22 Origin of Computer Compute(verb) To determine the outcomes (for examples, calculated numbers, amounts) by mathematics or by algorithmic procedures Computer(noun) A device that performs computation

23 Before Electronic Computer: Mechanical Computer E.g., Babbage difference machine (mid 19 century ) To tabulate polynomial functions Basic building block: gears

24 This image cannot currently be displayed. Before Electronic Computer: Human Computer Person manually performing math calculations Computer room at NASA High Speed Flight Station (1940s)

25 Electronic Computer (Hardware) Basic building blocks Vacuum tube Transistor IC (Integrated Circuit) VLSI (Very Large-Scale Integrated circuit)

26 First Vacuum Tube Based Computer ENIAC (Electronic Numerical Integrator And Computer) First general-purpose electronic computer Contained 17,000 (0.017 million) vacuum tubes Weigh 30 tons and consume 150 K Watts Completed in 1946 Originally designed to calculate artillery firing tables

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28 First Computer Bug A moth found trapped between relays Must debug the machine to remove the error

29 Origin of Computer Software Turing Machine by Alan Turing at Punch Card: 1940 s Punch Card

30 Modern Computer Based on similar concept The size of transistor is continuously reduced Size is measured in 0.03 micron (10-6 meter) range in today s processor In comparison, the diameter of human hair is around 100 micron A chip (size of a finger nail) contains billions of transistors

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32 Intel Core-i7

33 Overview of Computer Systems Computers, Programs, and Program Languages

34 What is a Computer System? Hardware of a computer consists of a CPU, memory, hard disk, USB driver, monitor, printer, and communication devices. Bus Storage Devices Memory CPU Communication Devices Input Devices Output Devices e.g., Disk, CD, and Tape e.g., Modem, and NIC e.g., Keyboard, Mouse e.g., Monitor, Printer

35 CPU The central processing unit (CPU) is the brain of a computer. It retrieves instructions from memory and executes them. The CPU speed is measured in megahertz (MHz), with 1 megahertz equaling 1 million pulses per second. The speed of the CPU has been improved continuously. If you buy a PC now, you can get an Intel Pentium 4 Processor at 3 gigahertz (1 gigahertz is 1000 megahertz). Bus Storage Devices Memory CPU Communication Devices Input Devices Output Devices e.g., Disk, CD, and Tape e.g., Modem, and NIC e.g., Keyboard, Mouse e.g., Monitor, Printer

36 Memory (Random Access Memory) Memory is to store data and program instructions for CPU to execute. A memory unit is an ordered sequence of bytes, each holds eight bits. A program and its data must be brought to memory before they can be executed. A memory byte is never empty, but its initial content may be meaningless to your program. The current content of a memory byte is lost whenever new information is placed in it. Bus Storage Devices Memory CPU Communication Devices Input Devices Output Devices e.g., Disk, CD, and Tape e.g., Modem, and NIC e.g., Keyboard, Mouse e.g., Monitor, Printer

37 How Data is Stored? Data of various kinds, such as numbers, characters, and strings, are encoded as a series of bits (zeros and ones). Computers use zeros and ones because digital devices have two stable states, which are referred to as zeroand oneby convention. The programmers need not to be concerned about the encoding and decoding of data, which is performed automatically by the system based on the encoding scheme. The encoding scheme varies. For example, character J is represented by in one byte. A small number such as three can be stored in a single byte. If computer needs to store a large number that cannot fit into a single byte, it uses a number of adjacent bytes. No two data can share or split a same byte. A byte is the minimum storage unit. Memory address Memory content Encoding for character J Encoding for character a Encoding for character v Encoding for character a Encoding for number 3

38 Data Representation in a Computer Use digital signals in electronic computer Us two voltage levels for two values: e.g., +5V for logic 1 and 0V for logic 0 Bit (short for binary digit): Two discrete logic values : 0 and 1 Since we only have two values, a bit alone can only represent two status: (won, lost) or (yes, no) or (true, false)

39 Combine Bits into Patterns If we group multiple bits, we can represent a very large number of different status Arranging bits into n-length sequences, we can create 2 n symbols 2 bits: 4 (= 2 2 ) possible symbols: 00, 01, 10, 11 Byte ( = 8 bits) 256 (=2 8 ) possible symbols: , ,, , Word (32 bits) About 4 billion (i.e., 2 32 ) possible symbols Word (64 bits) Current Computer How many possible symbols?? 2 64!

40 Size of Disk Storage to Store Data I Byte = 8 bits 1 KiloByte= 1024 (2 10 ) Bytes 1 MegaByte= 1024 (2 10 ) KBytes~= 1 million Bytes 1 GigaByte= 1024 (2 10 ) MBytes 1 TeraByte= 1024 (2 10 ) Gbytes~= 1 million MegaBytes 1 PetaByte= 1024 (2 10 ) Tbytes 1 ExaByte= 1024 (2 10 ) Pbytes~= 1 million TeraBytes

41 Storage Devices Memory is volatile, because information is lost when the power is off. Programs and data are permanently stored on storage devices and are moved to memory when the computer actually uses them. There are three main types of storage devices:disk drives (hard disks and floppy disks), CD drives (CD-R and CD-RW), and Tape drives. Bus Storage Devices Memory CPU Communication Devices Input Devices Output Devices e.g., Disk, CD, and Tape e.g., Modem, and NIC e.g., Keyboard, Mouse e.g., Monitor, Printer

42 Output Devices: Monitor The monitor displays information (text and graphics). The resolution and dot pitch determine the quality of the display. Bus Storage Devices Memory CPU Communication Devices Input Devices Output Devices e.g., Disk, CD, and Tape e.g., Modem, and NIC e.g., Keyboard, Mouse e.g., Monitor, Printer

43 Monitor Resolution and Dot Pitch resolution The screen resolution specifies the number of pixels in horizontal and vertical dimensions of the display device. Pixels (short for picture elements ) are tiny dots that form an image on the screen. A common resolution for a 17-inch screen, for example, is 1,024 pixels wide and 768 pixels high. The resolution can be set manually. The higher the resolution, the sharper and clearer the image is. dot pitch The dot pitch is the amount of space between pixels, measured in millimeters. The smaller the dot pitch, the sharper the display.

44 Communication Devices A regular modem uses a phone line and can transfer data in a speed up to 56,000 bps (bits per second). A DSL (digital subscriber line) also uses a phone line and can transfer data in a speed 20 times faster than a regular modem. A cable modem uses the TV cable line maintained by the cable company. A cable modem is as fast as a DSL. Network interface card (NIC) is a device to connect a computer to a local area network (LAN). The LAN is commonly used in business, universities, and government organizations. A typical type of NIC, called 10BaseT, can transfer data at 10 mbps (million bits per second). Wireless Network! Bus Storage Devices Memory CPU Communication Devices Input Devices Output Devices e.g., Disk, CD, and Tape e.g., Modem, and NIC e.g., Keyboard, Mouse e.g., Monitor, Printer

45 Programs Computer programs, known as software, are instructions to the computer. You tell a computer what to do through programs. Without programs, a computer is an empty machine. Computers do not understand human languages, so you need to use computer languages to communicate with them. Programs are written using Programming Languages.

46 Programming Languages Machine Language Assembly Language High-Level Language Machine language is a set of primitive instructions built into every computer. The instructions are in the form of binary code, so you have to enter binary codes for various instructions. Program with native machine language is a tedious process. Moreover the programs are highly difficult to read and modify. For example, to add two numbers, you might write an instruction in binary like this:

47 Programming Languages Machine Language Assembly Language High-Level Language Assembly languages were developed to make programming easy. Since the computer cannot understand assembly language, however, a program called assembler is used to convert assembly language programs into machine code. For example, to add two numbers, you might write an instruction in assembly code like this: ADDF3 R1, R2, R3

48 Programming Languages Machine Language Assembly Language High-Level Language The high-level languages are English-like and easy to learn and program. For example, the following is a high-level language statement that computes the area of a circle with radius 5: area = 5 * 5 * ;

49 Interpreting/Compiling Source Code A program written in a high-level language is called a source program orsource code. Because a computer cannot understand a source program, a source program must be translated into machine code for execution. The translationcan be done using another programming tool called an interpreter or a compiler.

50 Interpreting Source Code An interpreter reads one statement from the source code, translates it to the machine code or virtual machine code, and then executes it right away, as shown in the following figure. Note that a statement from the source code may be translated into several machine instructions.

51 Compiling Source Code A compiler translates the entire source code into a machine-code file, and the machine-code file is then executed, as shown in the following figure.

52 Operating Systems (OS) The operating system(os) is a program that manages and controls a computer s activities. The popular operating systems for general-purpose computers are Microsoft Windows, Mac OS, and Linux. Application programs, such as a Web browser or a word processor, cannot run unless an operating system is installed and running on the computer.

53 Popular High-Level Languages Language Description Ada BASIC C C++ C# COBOL FORTRAN Java Pascal Python Visual Basic Named for Ada Lovelace, who worked on mechanical general-purpose computers. The Ada language was developed for the Department of Defense and is used mainly in defense projects. Beginner s All-purpose Symbolic Instruction Code. It was designed to be learned and used easily by beginners. Developed at Bell Laboratories. C combines the power of an assembly language with the ease of use and portability of a high-level language. C++ is an object-oriented language, based on C. Pronounced C Sharp. It is a hybrid of Java and C++ and was developed by Microsoft. COmmon Business Oriented Language. Used for business applications. FORmula TRANslation. Popular for scientific and mathematical applications. Developed by Sun Microsystems, now part of Oracle. It is widely used for developing platformindependent Internet applications. Named for Blaise Pascal, who pioneered calculating machines in the seventeenth century. It is a simple, structured, general-purpose language primarily for teaching programming. A simple general-purpose scripting language good for writing short programs. Visual Basic was developed by Microsoft and it enables the programmers to rapidly develop graphical user interfaces.

54 High Level Programming Language: Source Code in Java import java.util.scanner; public class CalculateCircleArea{ public static void main(string[] args) { Scanner input = new Scanner(System.in); // Enter radius of the circle System.out.print("Enter the radius circle: "); double radius = input.nextdouble(); double area = radius * radius * ; } System.out.println("The area is " + area); }

55 High Level Programming Language: Source Code in C #include<stdio.h> intmain() { float radius, area; printf("\nenter the radius of Circle : "); scanf_s("%f", &radius); area = 3.14 * radius * radius; printf("\narea of Circle : %f", area); getchar(); //just to make the console output to wait } return (0);

56 Hyper Text Mark Up Programming Language: Webpage in HTML (Source Code)

57 Hyper Text Mark Up Programming Language: Webpage in HTML (Source Code)

58 High Level Programming Language : Java Java enables users to develop and deploy applications on the Internet for servers, desktop computers, and small hand-held devices. The future of computing is being profoundly influenced by the Internet, and Java promises to remain a big part of that future. Java is the Internet programming language. Java is a general purpose programming language. Java is the Internet programming language. 58

59 JDK Editions Java Standard Edition (J2SE) J2SE can be used to develop client-side standalone applications or applets. Java Enterprise Edition (J2EE) J2EE can be used to develop server-side applications such as Java servlets, Java ServerPages, and Java ServerFaces. Java Micro Edition (J2ME). J2ME can be used to develop applications for mobile devices such as cell phones. This book uses J2SE to introduce Java programming. 59

60 Popular IDE (Integrated Development Environment) Java: NetBeans Eclipse C/C++ MS Visual Studio 60

61 Algorithms The procedures for strategies that define how a program should organized and be executed to achieve the required tasks. Many different algorithms for a same task so the most efficient and optimized one should be selected to program.

62 Data Structures Structures hold data that belong togetherin a program that are used to compute or execute the tasks Examples: Student record: id, name, major, gender, start year, gpa Bank account: account number, name, currency, balance Address book: name, address, telephone number In database applications, structures are called records.

63 Different types of data in each row structure in Table Employee Employee ID Name DeptID Salary Project 10 Nemo Company Picnic 20 Dory Big data Project 40 Gill Factory Sensor Project 52 Ray Cloud Project

64 A Simple Java Program Listing 1.1 // This program prints Welcome to Java! public class Welcome { public static void main(string[] args) { System.out.println("Welcome to Java!"); } } Animation Welcome IMPORTANT NOTE: If you cannot run the buttons, see Run 64

65 Creating and Editing Using NotePad To use NotePad, type notepad Welcome.java from the DOS prompt. 65

66 Creating and Editing Using WordPad To use WordPad, type write Welcome.java from the DOS prompt. 66

67 Creating, Compiling, and Running Programs 67

68 Compiling Java Source Code You can port a source program to any machine with appropriate compilers. The source program must be recompiled, however, because the object program can only run on a specific machine. Nowadays computers are networked to work together. Java was designed to run object programs on any platform. With Java, you write the program once, and compile the source program into a special type of object code, known as bytecode. The bytecode can then run on any computer with a Java Virtual Machine, as shown below. Java Virtual Machine is a software that interprets Java bytecode. 68

69 Compiling and Running Java from the Command Window Set path to JDK bin directory set path=c:\program Files\java\jdk1.8.0\bin Set classpath to include the current directory set classpath=. Compile javac Welcome.java Run java Welcome 69

70 Compiling and Running Java from TextPad Save the file as Welcome.java File name matches with the class name in the source code with extension.java 70

71 Anatomy of a Programming Language Program name (Class name) Function (Method) Statements Statement terminator Reserved words Comments Blocks

72 Class Name Every Java program must have at least one class. Each class has a name. By convention, class names start with an uppercase letter. In this example, the class name is Welcome. // This program prints Welcome to Java! public class Welcome { public static void main(string[] args) { System.out.println("Welcome to Java!"); } }

73 Main Method Line 2 defines the main method. In order to run a class, the class must contain a method named main. The program is executed from the main method. // This program prints Welcome to Java! public class Welcome { public static void main(string[] args) { System.out.println("Welcome to Java!"); } }

74 Statement A statement represents an action or a sequence of actions. The statement System.out.println("Welcome to Java!") in the program in Listing 1.1 is a statement to display the greeting "Welcome to Java!. // This program prints Welcome to Java! public class Welcome { public static void main(string[] args) { System.out.println("Welcome to Java!"); } }

75 Statement Terminator Every statement in Java ends with a semicolon (;). // This program prints Welcome to Java! public class Welcome { public static void main(string[] args) { System.out.println("Welcome to Java!"); } }

76 Reserved words Reserved words or keywords are words that have a specific meaning to the compiler and cannot be used for other purposes in the program. For example, when the compiler sees the word class, it understands that the word after class is the name for the class. // This program prints Welcome to Java! public class Welcome { public static void main(string[] args) { System.out.println("Welcome to Java!"); } }

77 Blocks A pair of braces in a program forms a block that groups components of a program. public class Test { public static void main(string[] args) { System.out.println("Welcome to Java!"); } } Method block Class block

78 Basic elements // (single line comment): anything after it until end of line will be ignored /* */(multi line comment): anything in between will be ignored { } (curly brackets): define when a block of code starts and ends ;(semicolon): each line of code must be ended with a semicolon

79 Special Symbols Character Name Description {} () [] // " " ; Opening and closing braces Opening and closing parentheses Opening and closing brackets Double slashes Opening and closing quotation marks Semicolon Denotes a block to enclose statements. Used with methods. Denotes an array. Precedes a comment line. Enclosing a string (i.e., sequence of characters). Marks the end of a statement.

80 { } // This program prints Welcome to Java! public class Welcome { public static void main(string[] args) { System.out.println("Welcome to Java!"); } }

81 ( ) // This program prints Welcome to Java! public class Welcome { public static void main(string[] args) { System.out.println("Welcome to Java!"); } }

82 ; // This program prints Welcome to Java! public class Welcome { public static void main(string[] args) { System.out.println("Welcome to Java!"); } }

83 // // This program prints Welcome to Java! public class Welcome { public static void main(string[] args) { System.out.println("Welcome to Java!"); } }

84 " " // This program prints Welcome to Java! public class Welcome { public static void main(string[] args) { System.out.println("Welcome to Java!"); } }

85 animation Trace a Program Execution Enter main method // This program prints Welcome to Java! public class Welcome { public static void main(string[] args) { System.out.println("Welcome to Java!"); } }

86 animation Trace a Program Execution Execute statement // This program prints Welcome to Java! public class Welcome { public static void main(string[] args) { System.out.println("Welcome to Java!"); } }

87 animation Trace a Program Execution // This program prints Welcome to Java! public class Welcome { public static void main(string[] args) { System.out.println("Welcome to Java!"); } } print a message to the console

88 Introducing Programming with an Example Listing 2.1 Computing the Area of a Circle This program computes the area of the circle. ComputeArea Animation Run IMPORTANT NOTE: If you cannot run the buttons, see

89 animation Trace a Program Execution public class ComputeArea{ /** Main method */ public static void main(string[] args) { double radius; double area; radius allocate memory for radius no value // Assign a radius radius = 20; // Compute area area = radius * radius * ; // Display results System.out.println("The area for the circle of radius " + radius + " is " + area); } }

90 animation Trace a Program Execution public class ComputeArea{ /** Main method */ public static void main(string[] args) { double radius; double area; // Assign a radius radius = 20; // Compute area area = radius * radius * ; // Display results System.out.println("The area for the circle of radius " + radius + " is " + area); } } radius area memory no value no value allocate memory for area

91 animation Trace a Program Execution public class ComputeArea{ /** Main method */ public static void main(string[] args) { double radius; double area; radius area assign 20 to radius 20 no value // Assign a radius radius = 20; // Compute area area = radius * radius * ; // Display results System.out.println("The area for the circle of radius " + radius + " is " + area); } }

92 animation Trace a Program Execution public class ComputeArea{ /** Main method */ public static void main(string[] args) { double radius; double area; // Assign a radius radius = 20; radius area memory // Compute area area = radius * radius * ; compute area and assign it to variable area // Display results System.out.println("The area for the circle of radius " + radius + " is " + area); } }

93 animation Trace a Program Execution public class ComputeArea{ /** Main method */ public static void main(string[] args) { double radius; double area; // Assign a radius radius = 20; radius area memory // Compute area area = radius * radius * ; // Display results System.out.println("The area for the circle of radius " + radius + " is " + area); } } print a message to the console

94 Reading Input from the Console 1. Create a Scanner object Scanner input = new Scanner(System.in); 2. Use the method nextdouble() to obtain to a double value. For example, System.out.print("Enter a double value: "); Scanner input = new Scanner(System.in); double d = input.nextdouble(); Animation ComputeAreaWithConsoleInput ComputeAverage Run Run

95 Identifiers An identifier is a sequence of characters that consist of letters, digits, underscores (_), and dollar signs ($). An identifier must start with a letter, an underscore (_), or a dollar sign ($). It cannot start with a digit. An identifier cannot be a reserved word. (See Appendix A, Java Keywords, for a list of reserved words). An identifier cannot be true, false, or null. An identifier can be of any length.

96 Variables A place to store data Must be declared first Must with a data type Most commonly used data type: integer int E.g., int a, b, index; // no initial value int PIN_LED=13; // with initial value

97 Variables // Compute the first area radius = 1.0; area = radius * radius * ; System.out.println("The area is + area + " for radius "+radius); // Compute the second area radius = 2.0; area = radius * radius * ; System.out.println("The area is + area + " for radius "+radius);

98 Declaring Variables int x; // Declare x to be an // integer variable; double radius; // Declare radius to // be a double variable; char a; // Declare a to be a // character variable;

99 Assignment Statements x = 1; // Assign 1 to x; radius = 1.0; // Assign 1.0 to radius; a = 'A'; // Assign 'A' to a;

100 Declaring and Initializing in One Step int x = 1; double d = 1.4;

101 Named Constants final datatype CONSTANTNAME = VALUE; final double PI = ; final int SIZE = 3;

102 Numerical Data Types Name Range Storage Size byte 2 7 to (-128 to 127) 8-bit signed short 2 15 to ( to 32767) 16-bit signed int 2 31 to ( to ) 32-bit signed long 2 63 to bit signed (i.e., to ) float Negative range: 32-bit IEEE E+38 to -1.4E-45 Positive range: 1.4E-45 to E+38 double Negative range: 64-bit IEEE E+308 to -4.9E-324 Positive range: 4.9E-324 to E+308

103 Reading Numbers from the Keyboard Scanner input = new Scanner(System.in); int value = input.nextint(); Method Description nextbyte() reads an integer of the byte type. nextshort() reads an integer of the short type. nextint() reads an integer of the int type. nextlong() reads an integer of the long type. nextfloat() reads a number of the float type. nextdouble() reads a number of the double type.

104 Numeric Operators Name Meaning Example Result + Addition Subtraction * Multiplication 300 * / Division 1.0 / % Remainder 20 % 3 2

105 Integer Division +,-,*,/,and% 5/2yieldsaninteger2. 5.0/2yieldsadoublevalue2.5 5%2yields1(theremainderofthedivision)

106 Calculating Area of Circle: Reading Input from a Console import java.util.scanner; public class CalculateCircleArea{ public static void main(string[] args) { double radius; double area; // Prompt Users to Enter radius of the circle Scanner input = new Scanner(System.in); System.out.print("Enter the radius circle: "); //Read the input from a console to the radius variable radius = input.nextdouble(); //Calculate the area of the circle using radius then store it to the Variable area area = radius * radius* ; } } //Display the result to the console (Standard Output) System.out.println("The area is " + area);

107 import javax.swing.joptionpane; public class CalculateAreaCircle { public static void main(string[] args) { double radius; double area; // Enter radius of the cylinder String radiusstring = JOptionPane.showInputDialog(null, "Enter radius of the circle", "Circle Area Calculator", JOptionPane.QUESTION_MESSAGE); // Convert string to double radius = Double.parseDouble(radiusString); area = radius * radius * ; JOptionPane.showMessageDialog ( null, "Area of Circle is " + area ); } } System.out.println("The Area of the Circle is " + area);

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109 Foot Meter Converter import javax.swing.joptionpane; public class FootToMeterConverter{ public static void main(string[] args) { double foot; double meter; // Enter in Foot to Convert String footstring = JOptionPane.showInputDialog(null, "Enter the length in Foot to Convert", "FootToMeterConverter", JOptionPane.QUESTION_MESSAGE); // Convert string to double foot = Double.parseDouble(footString); meter = * foot; JOptionPane.showMessageDialog(null, "The Length in Meter is " + meter ); System.out.println("The Length in Meter is " + meter); }

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111 Programming: Selections

112 Lab3: A Simple Math Learning Tool This example creates a program to let a first grader practice additions. The program randomly generates two single-digit integers number1 and number2 and displays a question such as What is 7 + 9? to the student. After the student types the answer, the program displays a message to indicate whether the answer is true or false. IMPORTANT NOTE: If you cannot run the buttons, see Animation AdditionQuiz Run 112

113 The boolean Type and Operators Often in a program you need to compare two values, such as whether iis greater than j. Java provides six comparison operators (also known as relational operators) that can be used to compare two values. The result of the comparison is a Boolean value: true or false. // b = 1 for true or 0 for false boolean b; b = (1 > 2); // b = 0 for false

114 Relational Operators Java Mathematics Name Example Result Operator Symbol (radius is 5) < < less than radius < 0 false <= less than or equal to radius <= 0 false > > greater than radius > 0 true >= greater than or equal to radius >= 0 true == = equal to radius == 0 false!= not equal to radius!= 0 true

115 Control structure: if-else Basic format: if (condition) { } // do something if condition is true else { // do something if condition is false (not true) }

116 Comparison Operators Simple Boolean expression is obtained from comparison operators: X == Y (x is equal to y) X!= Y (x is not equal to y) X < Y (x is less than y) X > Y (x is greater than y) X <= Y (x is less than or equal to y) X >= Y (x is greater than or equal to y)

117 Boolean Operators Complicated Boolean expression can be obtained by combining simpler expressions with Boolean operators: e1 && e2 ( logical and operator, returning true when both e1 and e2 are true) e1 e2 ( logical or operator, returning true when either e1 or e2 are true)!e1 ( logical not operator, returning true when e1 is false)

118 One-way if Statements if (boolean-expression) { statement(s); } if (radius >= 0) { area = radius * radius * PI; System.out.println("The area" + " for the circle of radius " + radius + " is " + area); }

119 Note if i > 0 { System.out.println("i is positive"); } (a) Wrong if (i > 0) { System.out.println("i is positive"); } (b) Correct if (i > 0) { System.out.println("i is positive"); } (a) Equivalent if (i > 0) System.out.println("i is positive"); (b)

120 The Two-way ifstatement if (boolean-expression) { statement(s)-for-the-true-case; } else { statement(s)-for-the-false-case; }

121 if-elseexample if (radius >= 0) { area = radius * radius * ; System.out.println("The area for the + circle of radius " + radius + " is " + area); } else { System.out.println("Negative input"); }

122 Multiple Alternative if Statements if (score >= 90.0) System.out.print("A"); else if (score >= 80.0) System.out.print("B"); else if (score >= 70.0) System.out.print("C"); else if (score >= 60.0) System.out.print("D"); else System.out.print("F"); Equivalent This is better if (score >= 90.0) System.out.print("A"); else if (score >= 80.0) System.out.print("B"); else if (score >= 70.0) System.out.print("C"); else if (score >= 60.0) System.out.print("D"); else System.out.print("F"); (a) (b)

123 Multi-Way if-else Statements

124 animation Trace if-else statement Suppose score is 70.0 The condition is false if (score >= 90.0) System.out.print("A"); else if (score >= 80.0) System.out.print("B"); else if (score >= 70.0) System.out.print("C"); else if (score >= 60.0) System.out.print("D"); else System.out.print("F");

125 animation Trace if-else statement Suppose score is 70.0 The condition is false if (score >= 90.0) System.out.print("A"); else if (score >= 80.0) System.out.print("B"); else if (score >= 70.0) System.out.print("C"); else if (score >= 60.0) System.out.print("D"); else System.out.print("F");

126 animation Trace if-else statement Suppose score is 70.0 The condition is true if (score >= 90.0) System.out.print("A"); else if (score >= 80.0) System.out.print("B"); else if (score >= 70.0) System.out.print("C"); else if (score >= 60.0) System.out.print("D"); else System.out.print("F");

127 animation Trace if-else statement Suppose score is 70.0 grade is C if (score >= 90.0) System.out.print("A"); else if (score >= 80.0) System.out.print("B"); else if (score >= 70.0) System.out.print("C"); else if (score >= 60.0) System.out.print("D"); else System.out.print("F");

128 animation Trace if-else statement Suppose score is 70.0 Exit the if statement if (score >= 90.0) System.out.print("A"); else if (score >= 80.0) System.out.print("B"); else if (score >= 70.0) System.out.print("C"); else if (score >= 60.0) System.out.print("D"); else System.out.print("F");

129 Lab3: A Simple Math Learning Tool This example creates a program to let a first grader practice additions. The program randomly generates two single-digit integers number1 and number2 and displays a question such as What is 7 + 9? to the student. After the student types the answer, the program displays a message to indicate whether the answer is true or false. IMPORTANT NOTE: If you cannot run the buttons, see Animation AdditionQuiz Run 129

130 Generating a Random Number import java.util.scanner; public class AdditionQuiz{ public static void main(string[] args) { int number1, number2, answer; // Generate Two Random Numbers from 1-10 number1 = (int)(math.random() * ); number2 = (int)(math.random() * ); System.out.print( "What is " + number1 +" + " + number2 + "? "); } }

131 Algorithm for A Simple Math Learning Tool AdditionQuiz{ 1. Generate two random numbers, save them to the variable number1, number2 2. Prompt user to answer what is number 1 + number 2 3. Read the user s answer from a console, save it to the variable answer 4. if (number1+ number2 == answer) Printout Correct! else Printout Wrong! }

132 import java.util.scanner; public class AdditionQuiz { public static void main(string[] args) { int number1; int number2; int answer; number1 = (int )(Math.random() * ); number2 = (int )(Math.random() * ); // Create a Scanner Scanner input = new Scanner(System.in); System.out.print( "What is " + number1 + " + " + number2 + "? "); answer = input.nextint(); } if ((number1 + number2) == answer) System.out.println("Correct, Hi Five!"); else System.out.println("Wrong, Try Again!"); }

133 Computer Science Labs and Projects Dept. of Electrical Engineering and Computer Science Cleveland State University

134 Engineering Design Process 1. Specify Identify a problem to be solved or an idea 2. Analyze and design Research and create a potential design solution 3. Implement Construct the prototyping system, process etc. 4. Test Verify and evaluate the design/implementation 5. Repeat steps 2 to 4 until testing is successful

135 Algorithms The procedures for strategies that define how a program should organized and be executed to achieve the required tasks. Many different algorithms for a same task so the most efficient and optimized one should be selected to program.

136 Data Structures Structures hold data that belong togetherin a program that are used to compute or execute the tasks Examples: Student record: id, name, major, gender, start year, gpa Bank account: account number, name, currency, balance Address book: name, address, telephone number In database applications, structures are called records.

137 Different types of data in each row structure in Table Employee Employee ID Name DeptID Salary Project 10 Nemo Company Picnic 20 Dory Big data Project 40 Gill Factory Sensor Project 52 Ray Cloud Project

138 Computer Science Lab 1 Installing a Programming Language Java in a Computer Learn How to Run a software (Program) in a Computer System

139 Computer Science Program Lab 2 Writing a Program that Calculates the Volume of a Cylinder 1. Read two inputs Radius of a Circle and Height of a Cylinder 2. Calculate the Volume of a Cylinder 3. Display the Calculated Volume of Cylinder

140 import java.util.scanner; public class CalculateCylinderVolume { public static void main(string[] args) { Scanner input = new Scanner(System.in); // Enter radius of the cylinder System.out.print("Enter the radius and length of a cylinder: "); double radius = input.nextdouble(); double length = input.nextdouble(); double area = radius * radius * ; double volume = area * length; } System.out.println("The area is " + area); System.out.println("The volume of the cylinder is " + volume); }

141 import javax.swing.joptionpane; public class UsingJOptionPane { public static void main(string[] args) { double radius; double length; double volume; // Enter radius of the cylinder String radiusstring = JOptionPane.showInputDialog(null, "Enter radius of the cylinder", "Cylinder Volume Calculator", JOptionPane.QUESTION_MESSAGE); // Convert string to double radius = Double.parseDouble(radiusString); // Enter length of the cylinder String lengthstring = JOptionPane.showInputDialog(null, "Enter length of the cylinder", "Cylinder Volume Calculator", JOptionPane.QUESTION_MESSAGE); // Convert string to double length = Double.parseDouble(lengthString); volume = radius * radius * *length; JOptionPane.showMessageDialog ( null, "Volume of Cylinder is " + volume ); } } System.out.println("The volume of the cylinder is " + volume);

142

143 Lab3: A Simple Math Learning Tool This example creates a program to let a first grader practice additions. The program randomly generates two single-digit integers number1 and number2 and displays a question such as What is 7 + 9? to the student. After the student types the answer, the program displays a message to indicate whether the answer is true or false. IMPORTANT NOTE: If you cannot run the buttons, see Animation AdditionQuiz Run 143

144 Generating a Random Number import java.util.scanner; public class AdditionQuiz{ public static void main(string[] args) { int number1, number2, answer; // Generate Two Random Numbers from 1-10 number1 = (int)(math.random() * ); number2 = (int)(math.random() * ); System.out.print( "What is " + number1 +" + " + number2 + "? "); } }

145 Algorithm for A Simple Math Learning Tool AdditionQuiz{ 1. Generate two random numbers, save them to the variable number1, number2 2. Prompt user to answer what is number 1 + number 2 3. Read the user s answer from a console, save it to the variable answer 4. if (number1+ number2 == answer) Printout Correct! else Printout Wrong! }

146 import java.util.scanner; public class AdditionQuiz { public static void main(string[] args) { int number1; int number2; int answer; number1 = (int )(Math.random() * ); number2 = (int )(Math.random() * ); // Create a Scanner Scanner input = new Scanner(System.in); System.out.print( "What is " + number1 + " + " + number2 + "? "); answer = input.nextint(); } if ((number1 + number2) == answer) System.out.println("Correct, Hi Five!"); else System.out.println("Wrong, Try Again!"); }

147 Computer Science Lab 4 Creating a Webpage