 2002 Prentice Hall. All rights reserved. 1 Lecture 1 Consolidation of first year work (part 1) Read all the chapters on your own Slides highlight important.

 2002 Prentice Hall. All rights reserved. 1 Lecture 1 Consolidation of first year work (part 1) Read all the chapters on your own Slides highlight important concepts only Do not learn from slides only Summary of chapters 1 through to 5 Homework at end of slides

 2002 Prentice Hall. All rights reserved. 2 Chapter 1 – Introduction to Computers, the Internet, the Web and C# Outline 1.1 Introduction 1.2 What Is a Computer? 1.3 Computer Organization 1.4 Evolution of Operating Systems 1.5 Personal Computing, Distributed Computing and Client/Server Computing 1.6 Machine Languages, Assembly Languages and High-level Languages 1.7 C, C++, Visual Basic.NET and Java 1.8 C# 1.9 Other High-level Languages 1.10 Structured Programming 1.11 Key Software Trend: Object Technology 1.12 Hardware Trends 1.13 History of the Internet and World Wide Web 1.14 World Wide Web Consortium (W3C) 1.15 Extensible Markup Language (XML)

 2002 Prentice Hall. All rights reserved. 3 Chapter 1 – Introduction to Computers, the Internet, the Web and C# Outline 1.16 Introduction to Microsoft.NET 1.17.NET Framework and the Common Language Runtime

 2002 Prentice Hall. All rights reserved. 4 1.7 C, C++, Visual Basic.NET and Java (III) Object-Oriented Programming –Uses objects Reusable software components Modeled after items in the real world –More productive than structured programming –Easier to understand, correct and modify

 2002 Prentice Hall. All rights reserved. 5 1.8 C# C# –Developed at Microsoft by a team led by Anders Hejlsberg and Scott Wiltamuth –Event driven, object oriented, visual programming language –Based from C, C++ and Java –Incorporated into.NET platform Web based applications can be distributed –Devices and desktop computers Programs that can be accessed by anyone through any device Allows communicating with different computer languages –Integrated Design Environment (IDE) Makes programming and debugging fast and easy Rapid Application Development (RAD)

 2002 Prentice Hall. All rights reserved. 6 1.11 Key Software Trend: Object Technology What is Object Technology? –Packaging scheme for creating software units Units are objects –Any noun can be represented as an object Date object, time object, car object –Have properties Size, color, weight –Perform actions Moving, sleeping, drawing –Defined in classes Specify general format Provide specific attributes and behaviors

 2002 Prentice Hall. All rights reserved. 7 1.11 Key Software Trend: Object Technology (II) Object-Oriented programming –Based on nouns Reflects way world is perceived –Advantages over structured programming More natural process –Results in better productivity Classes provide reusability –Microsoft Foundation Classes (MFC) Easier to maintain –Programs more understandable –Focus on behaviors and interactions –Less attention to details

 2002 Prentice Hall. All rights reserved. 8 1.16 Introduction to Microsoft.NET.NET initiative –Introduced by Microsoft (June 2000) Vision for embracing the Internet in software development –Independence from specific language or platform Applications developed in any.NET compatible language –Visual Basic.NET, Visual C++.NET, C# and more Programmers can contribute to applications using the language in which they are most competent –Architecture capable of existing on multiple platforms –New program development process Provides increased productivity

 2002 Prentice Hall. All rights reserved. 9 1.16 Introduction to Microsoft.NET (II) Key components of.NET –Web services Applications used over the Internet –Software reusability Web services provide solutions for wide variety of companies –Cheaper than developing one-time solutions that can’t be reused –Single applications perform all operations for a company via various Web services Manage taxes, bills, investments and more Pre-packaged components –Make application development quicker and easier –Developers no longer need to be concerned with details of components

 2002 Prentice Hall. All rights reserved. 10 1.16 Introduction to Microsoft.NET (III) Keys to interaction –XML and SOAP “Glue” that combines various Web services to form applications –XML gives meaning to data –SOAP allows communication to occur easily

 2002 Prentice Hall. All rights reserved. 11 1.16 Introduction to Microsoft.NET (IV) Other concepts –Universal data access Eliminates need to synchronize files –Updating multiple copies of same file to the most recent Data resides at one central location –Accessible by anyone with connection and proper authorization Data formatted appropriately for display on various devices –Same document seen on PC, PDA, cell phone and other devices –Additional information available at Microsoft Web site www.microsoft.com/net www.microsoft.com/net

 2002 Prentice Hall. All rights reserved. 12 1.17.NET Framework and the Common Language Runtime.NET Framework –Heart of.NET strategy Manages and executes applications and Web services Provides security, memory management and other programming capabilities –Includes Framework class library (FCL) Pre-packaged classes ready for reuse Used by any.NET language –Details contained in Common Language Specification (CLS) Submitted to European Computer Manufacturers Association to make the framework easily converted to other platforms –Executes programs by Common Language Runtime (CLR)

 2002 Prentice Hall. All rights reserved. 13 1.17.NET Framework and the Common Language Runtime (II) Common Language Runtime (CLR) –Central part of framework Executes Visual Basic.NET programs –Compilation process Two compilations take place –Programs compiled to Microsoft Intermediate Language (MSIL) Defines instructions for CLR –MSIL code translated into machine code Machine code for a particular platform

 2002 Prentice Hall. All rights reserved. 14 1.17.NET Framework and the Common Language Runtime (III) Why two compilations? –Platform independence.NET Framework can be installed on different platforms Execute.NET programs without any modifications to code –Language independence.NET programs not tied to particular language Programs may consist of several.NET-compliant languages Old and new components can be integrated Other advantages of CLR –Execution-management features Manages memory, security and other features –Relieves programmer of many responsibilities –More concentration on program logic

 2002 Prentice Hall. All rights reserved. 15 Chapter 2 – Introduction to the Visual Studio.NET IDE Outline 2.1Introduction 2.2Visual Studio.NET Integrated Development Environment (IDE) Overview 2.3Menu Bar and Toolbar 2.4Visual Studio.NET Windows 2.4.1 Solution Explorer 2.4.2 Toolbox 2.4.3 Properties Window 2.5Using Help 2.6Simple Program: Displaying Text and an Image

 2002 Prentice Hall. All rights reserved. 16 2.1 Introduction Visual Studio.NET –Microsoft’s Integrated Development Environment (IDE) –Program in a variety of.NET languages –Tools to edit and manipulate several file types

 2002 Prentice Hall. All rights reserved. 17 2.2 Visual Studio.NET Integrated Development Environment (IDE) Overview Fig. 2.1 Start Page in Visual Studio.NET. navigation buttons location bar recent projects buttons hidden window Start Page links

 2002 Prentice Hall. All rights reserved. 18 2.2 Visual Studio.NET Integrated Development Environment (IDE) –The My Profile screen Allows Visual Studio.NET customization –Keyboard preferences –Window layout preferences New project dialogue (Fig. 2.2) –C#.NET project Group of related files, images, and documentations –C#.NET solution Group of projects creating one or a group of applications –Windows Applications Anything that runs in the Windows OS –Microsoft Word –Microsoft Internet Explorer

 2002 Prentice Hall. All rights reserved. 19 Chapter 3 – Introduction to C# Programming Outline 3.1 Introduction 3.2 Simple Program: Printing a Line of Text 3.3 Another Simple Program: Adding Integers 3.4 Memory Concepts 3.5 Arithmetic 3.6 Decision Making: Equality and Relational Operators

 2002 Prentice Hall. All rights reserved. 20 3.1 Introduction Console applications –No visual components –Only text output –Two types MS-DOS prompt –Used in Windows 95/98/ME Command prompt –Used in windows 2000/NT/XP –Windows applications Forms with several output types Contain Graphical User Interfaces (GUIs)

 2002 Prentice Hall. All rights reserved. 21 3.2 Simple Program: Printing a line of text Comments –Comments can be created using //… –Multi-lines comments use /* … */ –Comments are ignored by the compiler –Used only for human readers Namespaces –Groups related C# features into a categories –Allows the easy reuse of code –Many namespaces are found in the.NET framework library –Must be referenced in order to be used White Space –Includes spaces, newline characters and tabs

 2002 Prentice Hall. All rights reserved. 22 3.2 Simple Program: Printing a line of text Keywords –Words that cannot be used as variable or class names or any other capacity –Have a specific unchangeable function within the language –Example: class –All keywords are lowercase Classes –Class names can only be one word long (i.e. no white space in class name ) –Class names are capitalized, with each additional English word capitalized as well (e.g., MyFirstProgram ) –Each class name is an identifier Can contain letters, digits, and underscores (_) Cannot start with digits Can start with the at symbol (@)

 2002 Prentice Hall. All rights reserved. 23 3.2 Simple Program: Printing a line of text –Class bodies start with a left brace ({) –Class bodies end with a right brace (}) Methods –Building blocks of programs –The Main method Each console or windows application must have exactly one All programs start by executing the Main method –Braces are used to start ({) and end (}) a method Statements –Anything in quotes (“) is considered a string –Every statement must end in a semicolon (;)

 2002 Prentice Hall. All rights reserved. 24 3.2 Simple Program: Printing a line of text Graphical User Interface –GUIs are used to make it easier to get data from the user as well as display data to the user –Message boxes Within the System.Windows.Forms namespace Used to prompt or display information to the user

 2002 Prentice Hall. All rights reserved. 26 3.2 Simple Program: Printing a Line of Text References folder Solution Explorer System.Windows.Forms reference Fig. 3.8Adding a reference to an assembly in Visual Studio.NET (part 2).

 2002 Prentice Hall. All rights reserved. 27 3.3 Another Simple Program: Adding Integers Primitive data types –Data types that are built into C# String, Int, Double, Char, Long 15 primitive data types (chapter 4) –Each data type name is a C# keyword –Same type variables can be declared on separate lines or on one line Console.ReadLine() –Used to get a value from the user input Int32.Parse() –Used to convert a string argument to an integer –Allows math to be preformed once the string is converted

 2002 Prentice Hall. All rights reserved. Outline 28 Addition.cs 1 // Fig. 3.11: Addition.cs 2 // An addition program. 3 4 using System; 5 6 class Addition 7 { 8 static void Main( string[] args ) 9 { 10 string firstNumber, // first string entered by user 11 secondNumber; // second string entered by user 12 13 int number1, // first number to add 14 number2, // second number to add 15 sum; // sum of number1 and number2 16 17 // prompt for and read first number from user as string 18 Console.Write( "Please enter the first integer: " ); 19 firstNumber = Console.ReadLine(); 20 21 // read second number from user as string 22 Console.Write( "\nPlease enter the second integer: " ); 23 secondNumber = Console.ReadLine(); 24 25 // convert numbers from type string to type int 26 number1 = Int32.Parse( firstNumber ); 27 number2 = Int32.Parse( secondNumber ); 28 29 // add numbers 30 sum = number1 + number2; 31 This is the start of class AdditionTwo string variables defined over two lines The comment after the declaration is used to briefly state the variable purpose These are three int s that are declared over several lines and only use one semicolon. Each is separated by a coma. Console.ReadLine is used to take the users input and place it into a variable. This line is considered a prompt because it asks the user to input data. Int32.Parse is used to convert the given string into an integer. It is then stored in a variable. The two numbers are added and stored in the variable sum.

 2002 Prentice Hall. All rights reserved. Outline 29 Addition.cs Program Output 32 // display results 33 Console.WriteLine( "\nThe sum is {0}.", sum ); 34 35 } // end method Main 36 37 } // end class Addition Please enter the first integer: 45 Please enter the second integer: 72 The sum is 117. Putting a variable out through Console.WriteLine is done by placing the variable after the text while using a marked place to show where the variable should be placed.

 2002 Prentice Hall. All rights reserved. 30 3.4 Memory Concepts Memory locations –Each variable is a memory location Contains name, type, size and value –When a new value is enter the old value is lost –Used variables maintain their data after use

 2002 Prentice Hall. All rights reserved. 32 3.5 Arithmetic Arithmetic operations –Not all operations use the same symbol Asterisk (*) is multiplication Slash (/) is division Percent sign (%) is the modulus operator Plus (+) and minus (-) are the same –Must be written in a straight line –There are no exponents Division –Division can vary depending on the variables used When dividing two integers the result is always rounded down to an integer To be more exact use a variable that supports decimals

 2002 Prentice Hall. All rights reserved. 33 3.5 Arithmetic Order –Parenthesis are done first –Division, multiplication and modulus are done second Left to right –Addition and subtraction are done last Left to right

 2002 Prentice Hall. All rights reserved. 38 3.6 Decision Making: Equality and Relational Operators The if structure –Used to make a decision based on the truth of the condition True: a statement is performed False: the statement is skipped over –The start of an if statement should not end in a semicolon (;) –Fig. 3.18 lists the equality and rational operators There should be no spaces separating the operators

 2002 Prentice Hall. All rights reserved. 41 Chapter 4 – Control Structures Part 1 Outline 4.1 Introduction 4.2 Algorithms 4.3 Pseudocode 4.4 Control Structures 4.5 if Selection Structure 4.6 if/else Selection Structure 4.7 while Repetition Structure 4.8 Formulating Algorithms: Case Study 1 (Counter-Controlled Repetition) 4.9 Formulating Algorithms with Top-Down, Stepwise Refinement: Case Study 2 (Sentinel-Controlled Repetition) 4.10 Formulating Algorithms with Top-Down, Stepwise Refinement: Case Study 3 (Nested Control Structures) 4.11 Assignment Operators 4.12 Increment and Decrement Operators 4.13Introduction to Windows Application Programming

 2002 Prentice Hall. All rights reserved. 42 4.1 Introduction Before writing a program –Understand the problem –Think of an approach –Understand building blocks –Use proven principals of structured programming

 2002 Prentice Hall. All rights reserved. 43 4.2 Algorithms Procedure –The actions a program will perform –The order these actions will be performed –Also called an algorithm Program control –The task of ordering a computers procedure correctly

 2002 Prentice Hall. All rights reserved. 44 4.3 Pseudocode Pseudocode –Artificial and informal language –Helps programmers to plan an algorithm –Similar to everyday English –Not an actual programming language –Converting simply replaces words with C# code –Can use either Pseudocode OR flowcharts

 2002 Prentice Hall. All rights reserved. 45 4.4 Control Structures Program of control –Program performs one statement then goes to next line Sequential execution –Different statement other than the next one executes Selection structure –The if and if/else statements –The goto statement No longer used unless absolutely needed Causes many readability problems Repetition structure –The while and do/while loops (chapter 5) –The for and foreach loops (chapter 5)

 2002 Prentice Hall. All rights reserved. 46 4.4 Control Structures Flow charts –Used to map program –Illustrates the order events will go in Rectangle used to show action Oval used to show beginning Circles used as connectors Diamonds used as decisions –Combination of control structures Stacking –Placing one after another Nesting –Inserting of one structure into another

 2002 Prentice Hall. All rights reserved. 49 4.5 if Selection Structure The if structure –Causes the program to make a selection –Chooses based on conditional Any expression that evaluates to a bool type True: perform an action False: skip the action –Single entry/exit point –Require no semicolon in syntax

 2002 Prentice Hall. All rights reserved. 51 4.6 if/else selection structure The if/else structure –Alternate courses can be taken when the statement is false –Rather than one action there are two choices –Nested structures can test many cases –Structures with many lines of code need braces ({) Can cause errors –Fatal logic error –Nonfatal logic error

 2002 Prentice Hall. All rights reserved. 53 4.7 while Repetition Structure Repetition Structure –An action is to be repeated Continues while statement is true Ends when statement is false –Contain either a line or a body of code Must alter conditional –Endless loop

 2002 Prentice Hall. All rights reserved. 55 4.11 Assignment Operators Assignment operators –Can reduce code x += 2 is the same as x = x + 2 –Can be done with all the math operators ++, -=, *=, /=, and %=

 2002 Prentice Hall. All rights reserved. 57 4.12 Increment and Decrement Operators Increment operator –Used to add one to the variable –x++ –Same as x = x + 1 Decrement operator –Used to subtract 1 from the variable –y-- Pre-increment vs. post-increment –x++ or x-- Will perform an action and then add to or subtract one from the value –++x or --x Will add to or subtract one from the value and then perform an action

 2002 Prentice Hall. All rights reserved. 60 4.13 Introduction to Windows Application Programming Inheritance –Base class a class from which another class inherits from –Derived class The class from which another class inherits –Classes inherit basics of a class Attributes (data) Behaviors (methods) –Prevents the continual rewriting of code

 2002 Prentice Hall. All rights reserved. 61 Chapter 5 – Control Structures: Part 2 Outline 5.1 Introduction 5.2 Essentials of Counter-Controlled Repetition 5.3 for Repetition Structure 5.4 Examples Using the for Structure 5.5 switch Multiple-Selection Structure 5.6 do/while Repetition Structure 5.7 Statements break and continue 5.8 Logical and Conditional Operators 5.9 Structured-Programming Summary

 2002 Prentice Hall. All rights reserved. 62 5.2 Essentials of Counter Controlled Repetition Counter controlled repetition –Control variable The variable used to determine if the loop continues –Initial value of the control variable –Incrementing/decrementing of the variable –The condition When the looping should continue

 2002 Prentice Hall. All rights reserved. Outline 63 WhileCounter.cs Program Output 1 // Fig. 5.1: WhileCounter.cs 2 // Counter-controlled repetition. 3 4 using System; 5 6 class WhileCounter 7 { 8 static void Main( string[] args ) 9 { 10 int counter = 1; // initialization 11 12 while ( counter <= 5 ) // repetition condition 13 { 14 Console.WriteLine( counter ); 15 counter++; // increment 16 17 } // end while 18 19 } // end method Main 20 21 } // end class WhileCounter 1234512345 This is where the counter variable is initialized. It is set to 1. The loop will continue until counter is greater than five (it will stop once it gets to six) The counter is incremented and 1 is added to it

 2002 Prentice Hall. All rights reserved. 64 5.3 for Repetition Structure The for repetition structure –Syntax: for (Expression1, Expression2, Expression3) Expression1 = names the control variable –Can contain several variables Expression2 = loop-continuation condition Expression3 = incrementing/decrementing –If Expression1 has several variables, Expression3 must have several variables accordingly –++counter and counter++ are equivalent –Variable scope Expression1 can only be used in the body of the for loop When the loop ends the variable expires

 2002 Prentice Hall. All rights reserved. 65 5.3 for Repetition Structure for (int counter = 1; counter <= 5; counter++ ) Initial value of control variableIncrement of control variable Control variablenameFinal value of control variable for keyword Loop-continuation condition Fig. 5.3Components of a typical for header.

 2002 Prentice Hall. All rights reserved. 66 5.3 for Repetition Structure counter++ Establish initial value of control variable. Determine if final value of control variable has been reached. counter <= 10 Console.WriteLine ( counter * 10 ); true false int counter = 1 Body of loop (this may be multiple statements) Increment the control variable. Fig. 5.4Flowcharting a typical for repetition structure.

 2002 Prentice Hall. All rights reserved. Outline 67 ForCounter.cs Program Output 1 // Fig. 5.2: ForCounter.cs 2 // Counter-controlled repetition with the for structure. 3 4 using System; 5 6 class ForCounter 7 { 8 static void Main( string[] args ) 9 { 10 // initialization, repetition condition and incrementing 11 // are all included in the for structure 12 for ( int counter = 1; counter <= 5; counter++ ) 13 Console.WriteLine( counter ); 14 } 15 } 1234512345 This is where the counter variable is initialized. It is set to 1. The loop will continue until counter is greater than five (it will stop once it gets to six) The counter is incremented (1 is added to it)

 2002 Prentice Hall. All rights reserved. 69 5.5 switch Multiple-Selection Structure The switch statement –Constant expressions String Integral –Cases Case ‘x’ : –Use of constant variable cases Empty cases The default case –The break statement Exit the switch statement

 2002 Prentice Hall. All rights reserved. Outline 70 SwitchTest.cs 1 // Fig. 5.10: SwitchTest.cs 2 // Counting letter grades. 3 4 using System; 5 6 class SwitchTest 7 { 8 static void Main( string[] args ) 9 { 10 char grade; // one grade 11 int aCount = 0, // number of As 12 bCount = 0, // number of Bs 13 cCount = 0, // number of Cs 14 dCount = 0, // number of Ds 15 fCount = 0; // number of Fs 16 17 for ( int i = 1; i <= 10; i++ ) 18 { 19 Console.Write( "Enter a letter grade: " ); 20 grade = Char.Parse( Console.ReadLine() ); 21 22 switch ( grade ) 23 { 24 case 'A': // grade is uppercase A 25 case 'a': // or lowercase a 26 ++aCount; 27 break; 28 29 case 'B': // grade is uppercase B 30 case 'b': // or lowercase b 31 ++bCount; 32 break; 33 Each of these variables acts as a counter so they are initialized to zero The start of the switch statement. The grade variable is used as the data to be tested for each case. Prompt the user for a grade and store it into the grade variable case ‘A’ is empty so it is the same as case ‘a’ Both cases add one to aCountThe break statement is used to exit the switch statement and not perform the rest of the operations Both case ‘B’ and case ‘b’ add one to the bCount variable A for loop that initializes i to 1, loops 10 times and increments i by one each time

 2002 Prentice Hall. All rights reserved. Outline 71 SwitchTest.cs 34 case 'C': // grade is uppercase C 35 case 'c': // or lowercase c 36 ++cCount; 37 break; 38 39 case 'D': // grade is uppercase D 40 case 'd': // or lowercase d 41 ++dCount; 42 break; 43 44 case 'F': // grade is uppercase F 45 case 'f': // or lowercase f 46 ++fCount; 47 break; 48 49 default: // processes all other characters 50 Console.WriteLine( 51 "Incorrect letter grade entered." + 52 "\nGrade not added to totals." ); 53 break; 54 55 } // end switch 56 57 } // end for 58 59 Console.WriteLine( 60 "\nTotals for each letter grade are:\nA: {0}" + 61 "\nB: {1}\nC: {2}\nD: {3}\nF: {4}", aCount, bCount, 62 cCount, dCount, fCount ); 63 64 } // end method Main 65 66 } // end class SwitchTest Both cases add 1 to cCountIf grade equals D or d add one to dCount Add one to fCount if grade equals F or fIf non of the cases are equal to the value of grade then the default case is executed Display the results

 2002 Prentice Hall. All rights reserved. Outline 72 SwitchTest.cs Program Output Enter a letter grade: a Enter a letter grade: A Enter a letter grade: c Enter a letter grade: F Enter a letter grade: z Incorrect letter grade entered. Grade not added to totals. Enter a letter grade: D Enter a letter grade: d Enter a letter grade: B Enter a letter grade: a Enter a letter grade: C Totals for each letter grade are: A: 3 B: 1 C: 2 D: 2 F: 1

 2002 Prentice Hall. All rights reserved. 74 5.6 do/while Repetition Structure The while loops vs. the do/while loops –Using a while loop Condition is tested The the action is performed Loop could be skipped altogether –Using a do/while loop Action is performed Then the loop condition is tested Loop must be run though once Always uses brackets ({) to prevent confusion

 2002 Prentice Hall. All rights reserved. Outline 75 DoWhileLoop.cs Program Output 1 // Fig. 5.12: DoWhileLoop.cs 2 // The do/while repetition structure. 3 4 using System; 5 6 class DoWhileLoop 7 { 8 static void Main( string[] args ) 9 { 10 int counter = 1; 11 12 do 13 { 14 Console.WriteLine( counter ); 15 counter++; 16 } while ( counter <= 5 ); 17 18 } // end method Main 19 20 } // end class DoWhileLoop 1234512345 The counter is initialized to oneThese actions are performed at least one Continue looping as long as counter is less than 6 The incrementing task

 2002 Prentice Hall. All rights reserved. 77 5.7 Statements break and continue Use –Used to alter the flow of control –The break statement Used to exit a loop early –The continue statement Used to skip the rest of the statements and begin the loop at the first statement in the loop –Programs can be completed without their usage

 2002 Prentice Hall. All rights reserved. Outline 78 BreakTest.cs 1 // Fig. 5.14: BreakTest.cs 2 // Using the break statement in a for structure. 3 4 using System; 5 using System.Windows.Forms; 6 7 class BreakTest 8 { 9 static void Main( string[] args ) 10 { 11 string output = ""; 12 int count; 13 14 for ( count = 1; count <= 10; count++ ) 15 { 16 if ( count == 5 ) 17 break; // skip remaining code in loop 18 // if count == 5 19 20 output += count + " "; 21 22 } // end for loop 23 24 output += "\nBroke out of loop at count = " + count; 25 26 MessageBox.Show( output, "Demonstrating the break statement", 27 MessageBoxButtons.OK, MessageBoxIcon.Information ); 28 29 } // end method Main 30 31 } // end class BreakTest Displays a message box the displays the output, has a title of “demonstrating the break statement,” uses an OK button, and displays an information icon A loop that starts at one, goes to ten, and increments by one If count = 5 then break out of the loopDisplay the last value that the counter was at before it broke

 2002 Prentice Hall. All rights reserved. Outline 80 ContinueTest.cs 1 // Fig. 5.15: ContinueTest.cs 2 // Using the continue statement in a for structure. 3 4 using System; 5 using System.Windows.Forms; 6 7 class ContinueTest 8 { 9 static void Main( string[] args ) 10 { 11 string output = ""; 12 13 for ( int count = 1; count <= 10; count++ ) 14 { 15 if ( count == 5 ) 16 continue; // skip remaining code in loop 17 // only if count == 5 18 19 output += count + " "; 20 } 21 22 output += "\nUsed continue to skip printing 5"; 23 24 MessageBox.Show( output, "Using the continue statement", 25 MessageBoxButtons.OK, MessageBoxIcon.Information ); 26 27 } // end method Main 28 29 } // end class ContinueTest A loop that starts at 1, goes to 10, and increments by 1 If count = 5 then continue looping causing the program to skip the rest of the loop Create a message box that displays the output, has the title “using the continue statement,” uses an OK button, and displays an information icon.

 2002 Prentice Hall. All rights reserved. 82 5.8 Logical and Conditional Operators Operators –Logical AND (&) –Conditional AND (&&) –Logical OR (|) –Conditional OR (||) –Logical exclusive OR or XOR (^) –Logical NOT (!) Can be avoided if desired by using other conditional operators Used to add multiple conditions to a statement

 2002 Prentice Hall. All rights reserved. 83 5.9 Structured Programming Summary Control Structures –Only one entrance –Only one exit –Building blocks to programming –Allow nesting –Makes code neater and easier to follow –No overlapping structures The goto keyword

 2002 Prentice Hall. All rights reserved. 84 5.9 Structured Programming Summary 3 forms of control necessary –Many ways to implement these controls –Sequential (only 1 way) Straight forward programming –Selection (3 ways) if selection (one choice) if/else selection (two choices) switch statement (multiple choices) –Repetition (4 ways) while structure do/while structure for structure foreach structure (chapter 7)

 2002 Prentice Hall. All rights reserved. 87 5.9 Structured Programming Summary Fig. 5.22C#’s single-entry/single-exit sequence, selection and repetition structures. (part 2) Selection T F if structure (single selection) else/if structure (double selection) TF switch structure (multiple selections). break T T T F F F.

 2002 Prentice Hall. All rights reserved. 88 5.9 Structured Programming Summary Fig. 5.22C#’s single-entry/single-exit sequence, selection and repetition structures. (part 3) Repetition T F while structure T F do/while structure F T for structure/ foreach structure

 2002 Prentice Hall. All rights reserved. 89 5.9 Structured Programming Summary Fig. 5.27Stacked, nested and overlapped building blocks. Stacked building blocks Overlapping building blocks (illegal in structured programs) Nested building blocks

 2002 Prentice Hall. All rights reserved. 91 Homework Read Chapters 1 to 5 –You may be tested on this work at ANY time! Practical (to be done ASAP) –Exercise 4.10 (page 137) Change gallons to litres Change miles to kilometres –Exercise 4.12 (page 137) –Exercise 4.13 (page 137/138) –Exercise 4.14 (page 138) –Exercise 5.4 (page 176) –Exercise 5.5 (page 176) –Exercise 5.9 (page 177) –Exercise 5.10 (page 177)

 2002 Prentice Hall. All rights reserved. 1 Lecture 1 Consolidation of first year work (part 1) Read all the chapters on your own Slides highlight important.

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 2002 Prentice Hall. All rights reserved. 1 Lecture 1 Consolidation of first year work (part 1) Read all the chapters on your own Slides highlight important.

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Presentation on theme: " 2002 Prentice Hall. All rights reserved. 1 Lecture 1 Consolidation of first year work (part 1) Read all the chapters on your own Slides highlight important."— Presentation transcript:

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