Outsource. Laboratories. Introduction to Programming with Microsoft Visual Basic.NET. Outsource Laboratories Press

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1 Outsource Laboratories Introduction to Programming with Microsoft Visual Basic.NET Outsource Laboratories Press

2 Copyright 2004 Outsource Laboratories Press. Printed in the United States of America ISBN OUTSOURCE LABORATORIES PRESS PO Box 187, Matawan, NJ USA For more information about Outsource Laboratories Press textbooks and services, contact us: Toll free: 888-GO-OLABS ( ) training@olabs.com Technical Support: Outsource Laboratories will offer limited technical support to instructors who have purchased classroom sets and have registered with Outsource Laboratories. Contact your representative for more information. All rights reserved. This product and related documentation is protected by copyright and distributed under license restricting its use, copying, distribution, and decompilation. No part of this book may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or by any information storage and retrieval system, without prior written authorization from the publisher. The authors and publisher have taken care in preparation of this book, but make no expressed or implied warranty of any kind and assume no responsibility for any errors or omissions. No liability is assumed for incidental or consequential damages in connection with or arising out of the information contained in this book. All other products referenced herein are trademarks of their respective holders. Visual Basic and.net are trademarks or registered trademarks of Microsoft Corporation in the United States and other countries. Java and all Java-based marks are trademarks or registered trademarks of Sun Microsystems, Inc. in the United States and other countries. OL ii

3 Table of Contents About Olabs Text xv 1 Basics of Programming Introduction What is Programming? A Brief History of Programming Early History Stored Program Computers - The Birth of Modern Computers Main Components Data Operations Machine Language Assembly Language High Level Languages Compilers and Interpreters Procedural Programming Languages Object-Oriented Programming Languages Steps for Developing a Program Step 1: Analyze the Problem Analyzing an Example Problem Exercise 1-1: Analyzing Simple Programming Problems Step 2: Design an Algorithm to Solve the Problem Pseudocode Flowcharts Exercise 1-2: Designing Algorithms Step 3: Implement the Algorithm using a Programming Language Step 4: Compile and Run the Program Step 5: Test and Debug the Program Step 6: Maintain the Program Steps in the Software Maintenance Process Review Questions Visual Basic.NET Programming Introduction Facts about Visual Basic.NET Facts about.net The.NET Framework Common Language Runtime NET Framework Class Library Types of Visual Basic.NET Programs iii

4 Table of Contents Console Applications Windows Applications Web Applications Windows Services Web Services Using Visual Studio.NET Launching Visual Studio. NET Configuring Visual Studio.NET Opening a Visual Basic.NET Project Main Components of the Visual Basic.NET IDE Compiling and Running a Visual Basic.NET Program Steps to Compile and Run a Program for Debug Purposes Steps to Compile and Run a Program for Release Purposes Exercise 2-1: Compile and Run Visual Basic.NET Programs Running a Program from a DOS Command Prompt Window Starting a Command Prompt Window Changing into a Different Directory Listing All Files in a Directory A Few Words About Files and Filenames Running an Executable Program from the Command Prompt Creating a Simple Visual Basic.NET Program Creating a New Visual Basic.NET Project Laying Out the GUI Setting Form/Control Properties Writing Event Handling Code Exercise 2-2: Creating a GUI Exercise 2-3: Implementing Event Handlers Basic Structure of a Visual Basic.NET Program Exercise 2-4: The Sub Main Procedure Comments in Visual Basic.NET Exercise 2-5: Using Comments Review Questions Variables, Data Types and Operators Introduction The Add2Numbers Program Statements and Expressions Variables Declaring Variables Assigning Values to Variables Variable Names Exercise 3-1: Identify Valid Variable Names Data Types Strongly Typed v. Weakly Typed Languages Visual Basic.NET s Primitive Data Types iv

5 Main Data Types Used in Programming The Data Type Integer Exercise 3-2: Declare a Variable of Type Integer Exercise 3-3: Assign Values to Variables of Type Integer The Data Type Double Exercise 3-4: Declare a Variable of Type Double Exercise 3-5: Assign Values to Variables of Type Double Assigning a Value When Declaring a Variable The Data Type Char Exercise 3-6: Declare a Variable of Type Char Exercise 3-7: Assign Values to Variables of Type Char Exercise 3-8: Identify Values of Type Char The Data Type String Printing Strings Exercise 3-9: Working with the String Data Type The Data Type Boolean Exercise 3-10: Working with the Boolean Data Type Exercise 3-11: Map Values to Variables Literals Literal Type Characters Type Conversion and Type Casting Constants Arithmetic Operators Addition Operator Subtraction Operator Multiplication Operator Division Operators Modulo Operator Exercise 3-12: Using Operators Exercise 3-13: Bills Calculator Program Exercise 3-14: Calculating the Average Mark Exercise 3-15: Calculate the Weekly Salary Arithmetic/Assignment Operators Exercise 3-16: Using Arithmetic/Assignment Operators Order of Operations - Precedence of Operators Exercise 3-17: Change the Order of Operations Review Questions Flow Control - Selection Introduction What is Flow Control? Selection Statements Comparison Operators Exercise 4-1: Using Comparison Operators v

6 Table of Contents Logical Operators AND Operator OR Operator NOT Operator Exercise 4-2: Using Logical Operators Types of If Statements The If-Then-Else Statement The If Statement Without Else Exercise 4-3: Using an If-Then-Else Statement Exercise 4-4: Reef Cruise Reservation System Multiple If Statements Exercise 4-5: Understanding Multiple If-Statements Exercise 4-6: Fastfood Ordering System The Select-Case Statement Exercise 4-7: Using the Select-Case Statement Review Questions Flow Control - Repetition Introduction Repetition Statements Counter v. Sentinel-Controlled Loops The While Loop Exercise 5-1: Keeping Track of Variables in a While Loop Exercise 5-2: Debt Calculator Program The Do-While Loop Exercise 5-3: Bonus Notifier Program The For Loop Exercise 5-4: Name Decorator Program Exercise 5-5: Selecting the Appropriate Loop Review Questions Procedures Introduction Modularity: The Reason Behind Procedures The Sub Procedure Parameters of a Procedure What are Parameters? Passing Parameters to a Procedure Function Procedures Exercise 6-1: Identifying Parts of a Function Procedure Exercise 6-2: Calling Procedures Exercise 6-3: Modularizing a Program Using a Function Procedure Inside a Statement as an Operand Examples of Program Modularization using Procedures vi

7 Example 1 - CostCalculator Example 2 - Convert Inches to Centimeters Exercise 6-4: Converting Currencies Review Questions Arrays Introduction What is an Array? Declaring an Array Variable Creating an Array Array Values Known at Compile Time Exercise 7-1: Creating an Array Array Values Known at Run Time Assigning Values to an Array Assigning a Value to an Array Element Variables/Expressions as Indices Exercise 7-2: Identifying Array Elements Retrieving Values from an Array Retrieving an Array Element Retrieving All Array Elements The GetUpperBound Property Common Problem: Array Index Out of Range Example Array Scenarios Scenario 1: Representing Rows of People in a Theater Scenario 2: Weekday Translation Program Exercise 7-3: The Weekdays Program Scenario 3: Summing Up an Array of Prices Scenario 4: Finding Lowest Price in Array of Prices Scenario 5: Storing Student Names Exercise 7-4: Storing Student Marks Application Command Line Parameters Exercise 7-5: Fibonacci Numbers Multi-Dimensional Arrays Declaring a Multi-Dimensional Array Variable Creating a Multi-Dimensional Array Assigning Values to a Multi-Dimensional Array Retrieving Values from a Multi-Dimensional Array Exercise 7-6: Storing Team Scores Review Questions Strings Introduction Strings Creating a String vii

8 Table of Contents Exercise 8-1: Creating String Literals Immutability of Strings String Methods Exercise 8-2: Using String Methods I Common String Manipulations Concatenation Exercise 8-3: Using Concatenation Operators Exercise 8-4: Concatenating Static and Dynamic Strings Substrings Exercise 8-5: Substrings Comparisons Tokenizing Exercise 8-6: Tokenizing Strings Mutable Strings - StringBuilder Declaring and Creating a StringBuilder StringBuilder Methods Common StringBuilder Manipulations Exercise 8-7: Modifying a StringBuilder Review Questions Introduction to Object Oriented Programming and UML Introduction What is Object Oriented Programming? Classes Defining a Class Exercise 9-1: Interpreting UML Class Notation Encapsulation Exercise 9-2: Using Encapsulation to Define a Class Inheritance Exercise 9-3: Inheritance Concept Abstract Classes Interfaces Code for our Class Using a Class Creating Objects from a Class Exercise 9-4: Creating Objects from Classes More UML Diagram Notation Representing a Single Class Exercise 9-5: Draw a Class Diagram for a Single Class Representing Class-Object Relationship Exercise 9-6: Drawing a Class-Object Relationship Diagram Representing Class Relationships Exercise 9-7: Representing Class Associations Exercise 9-8: Representing Cardinality of Relationships viii

9 Inheritance Relationships Exercise 9-9: Inheritance Relationship Diagrams Review Questions Using Objects Introduction More About Objects Why Are Objects Important? Where do Objects Come From? A World of Objects Exercise 10-1: Objects Declaring Object Variables Creating Objects Accessing Object Attributes and Properties Access Modifiers Exercise 10-2: Creating and Using Objects Invoking Object Methods Member Signatures The Me Reference Using the.net Framework Class Library Initializing Objects with Constructors Person Class Members Procedure and Constructor Overloading Exercise 10-3: Using the Person Class Objects with Multiple Aliases (Shared Objects) Side Effects of Multiple Aliases Garbage Collection The Null Reference Dereferencing a Null Reference The CD Database System Exercise: The Database Class Exercise 10-4: The CD Database System Review Questions Developing Classes Introduction Steps to Create a Class Case Study: A Banking Application Step 1: Name the Class A Minimal Class Definition Exercise 11-1: A Minimally-Defined Class Step 2: Determine and Declare the Attributes and Properties Exercise 11-2: Class Attributes and Properties Step 3: Determine, Define, and Implement the Methods Step 3a: Defining Methods - Determine Operations ix

10 Table of Contents Step 3b: Defining Methods - Define Signatures and Return Types Naming Conventions for Visual Basic.NET Methods Case Study Example: Determine and Define the Methods Step 3c: Implement the Methods How Method Calls Work Implementing the Deposit and Withdraw Methods Local Variable Declarations Methods Implemented in BankAccount Class Exercise 11-3: Implementing Methods Initializing Objects: Constructors Revisited Creating a No-Argument Constructor Overloaded Constructors Exercise 11-4: Define a Constructor Inheritance Revisited The Inherits Statement Using Inheritance The MyBase Keyword Polymorphism The Object Class Abstract Classes Revisited The MustInherit Keyword Using an Abstract Class Interfaces Revisited Visual Basic.NET s IComparable Interface The Implements Statement Using Interfaces Type Casting of Objects Up-Casting Down-Casting Access Modifiers: Private, Public and Protected The Shared Modifier Visual Basic.NET s Math Class Exercise 11-5: Using a Shared Attribute Exercise 11-6: A Banking Application Review Questions Data Structures Introduction What are Data Structures? Stacks Stack Operations Implementing a Stack Using an Array Stack Example Exercise 12-1: Using the StackArray Class Queues Queue Operations x

11 Implementing a Queue Using an Array Queue Example Exercise 12-2: Using the QueueArray Class Linked Lists Linked List vs. Array Linked List Operations Implementation of a Linked List Linked List Example Exercise 12-3: Implementing a Stack using a Linked List Exercise 12-4: Implementing a Queue using a Linked List Recursion Example Problem that Cannot be Solved Using Recursion Example Problem that Can be Solved Using Recursion Exercise 12-5: Find the Nth Number in a Fibonacci Sequence Binary Tree Binary Search Tree Binary Search Tree Operations Inserting an Item Locating an Item Deleting an Item Tree Traversal Implementation of a Binary Search Tree Binary Tree Example Exercise 12-6: Using the BinaryTree Class Exercise 12-7: Inserting Data Into a Binary Search Tree Exercise 12-8: Traversing a Binary Search Tree The ArrayList Class Methods of the ArrayList Class Example Using the ArrayList Class Enumerating Over an ArrayList Exercise 12-9: Using the ArrayList Class The Hashtable Class Enumerating Over a Hashtable Exercise 12-15: Using the Hashtable Class Review Questions Exception Handling Introduction What is an Exception? How Visual Basic.NET Handles Exceptions Exercise 13-1: Visual Basic.NET Exceptions Exception Handling with Try-Catch-Finally The Try Block The Catch Block Catching Multiple Exceptions The Finally Block xi

12 Table of Contents Exercise 13-2: Catching Exceptions Exercise 13-3: More on Catching Exceptions Exception Handling with Throw Statement Propagating Exceptions Exceptions Example Visual Basic.NET Exception Hierarchy User-Defined Exceptions Exercise 13-4: User-Defined Exceptions Review Questions Visual Basic.NET I/O Introduction What is I/O? Streams Readers and Writers Text File I/O Reading from a Text File Writing to a Text File Exercise 14-1: Reading and Writing Text Files Exercise 14-2: Reading and Writing Files (optional) Review Questions The First Bank of VB GUI: A Case Study15-1 Introduction First Bank of VB GUI Requirements: General First Bank of VB GUI Requirements: Use Cases First Bank of VB GUI Requirements: The User Interface The Login Screen The Main Application Screen The Create Customer Screen The Create Account Screen The Customer Details Screen The Account Details Screen The Search Screen Persistent Data Storage Implementing the First Bank of VB GUI Creating a GUI with Multiple Forms Creating a Menubar Using Panels Using Message Boxes Exercise 15-1: Creating the Login Screen Exercise 15-2: Creating a Menubar for the Main Screen Exercise 15-3: Creating the Create Customer Screen xii

13 Exercise 15-4: Handling Login Events Exercise 15-5: Handling Menu Item Events Exercise 15-6: Handling Create Customer Events Exercise 15-7: Handling Deposit/Withdrawal Events Review Questions Index I-1 xiii

14 Index A Abs function abstract classes 9-15, abstract methods 9-15 access modifiers 10-10, accessors 9-5, 11-7 Get and Set accessors 9-10 Ada Lovelace 1-3 addition operator 3-38 algorithm 1-15 Analytical Engine 1-3 And operator 4-6 AndOr operator 4-7 Arithmetic Logic/Unit (ALU) 1-4 array element 7-1 array index 7-1 ArrayList class arrays assigning values 7-8 creation 7-5 declaration 7-4 definition 7-1 GetUpperBound property 7-14 multi-dimensional arrays 7-32 retrieving values 7-11 variable/expressions as indices 7-9 assembly language 1-6 assignment operator 3-7 attributes 1-9, 11-6 B binary number 1-4 binary search tree implementation operations binary tree traversal bit 1-4 Boolean data type 3-30 Button control adding to a form 2-38 handling button click events 2-44 setting properties 2-42 byte-oriented streams 14-3 C cardinality 9-31 Catch block 13-6 Central Processing Unit (CPU) 1-4 Char data type 3-22 literal type characters 3-34 character-oriented streams 14-3 Charles Babbage 1-3 class 1-9, 9-3 abstract class 9-15 attributes 9-5, 11-6 concrete class 9-15 creating objects 9-22 creation 11-2 defining a class 9-5 implementing methods methods 9-7, naming conventions 11-3 properties 9-6, 11-6 UML notation 9-5 Class keyword 2-51 class-object relationship 9-29 Code Editor Window 2-20 ComboBox control adding to a form 2-37 handling combo box keyboard input events 2-45 setting properties 2-42 command-line parameters 7-30 comments 2-53 Common Language Runtime 2-6 comparison operators 4-4 compiler 1-8 computer I-1

15 Introduction to Programming with Microsoft Visual Basic.NET Index architecture 1-3 main components 1-4 Concatenation operators 8-9 concrete class 9-15 console applications 2-8 Const keyword 3-36 constants 3-36 constructor 10-8, object initialization overloading 10-18, Control Unit (CU) 1-4 counter-controlled loops 5-3 CType function 3-35 D data hiding 9-10 data structures ArrayList class binary search tree binary tree Hashtable class linked lists queues 12-8 stacks 12-3 data types 3-9 constants 3-36 main programming data types 3-12 primitive data types 3-11 reference data types 3-11 strongly typed languages 3-10 value data types 3-11 weakly typed languages 3-10 default constructor Dim keyword 3-6 divide and conquer 6-2 division operators 3-44 DOS cd command 2-28 dir command 2-28 dot operator 10-9, Double data type 3-16 Do-While loop 5-2, 5-10 E encapsulation 9-3, 9-10 ENIAC 1-3 event handlers 2-21 event handling in Visual Basic.NET 2-43 event-driven programming 2-2 exception how Visual Basic.NET handles them 13-3 try block 13-6 exception handlers 13-5 generalized 13-8 specialized 13-8 Try-Catch-Finally blocks 13-5 exceptions catching multiple exceptions 13-8 class hierarchy code example exception handlers 13-5 Throw statement user-defined expression 3-4 F File I/O 14-4 FileNotFoundException 13-5 Finally block 13-9 First Bank of VB GUI 15-1 flow control 4-2 repetition 5-2 selection 4-2 flowcharts 1-18 For loop 5-2, 5-14 Form Design Window 2-20 forms 2-20 adding controls 2-35 resizing 2-35 setting as Startup object setting properties 2-40 showing and hiding Function procedures 6-9 G garbage collection 2-6, Get accessor 9-10, 11-7 GetUpperBound property 7-14 graphical user interface 1-9 See also GUI GUI 1-9 creating a menubar First Bank of VB GUI 15-1 using message boxes using panels with multiple forms H Hashtable class high level language 1-7 I I/O 14-2 readers 14-3 reading from a text file 14-4 streams 14-2 writers 14-3 I-2

16 Introduction to Programming with Microsoft Visual Basic.NET Index writing to a text file 14-5 IComparable interface If-statement without Else 4-14 If-Then-Else statement 4-9 immutability of strings 8-5 Implements statement IndexOutOfRangeException 7-15 inheritance 9-12, UML notation 9-12 Inherits statement inorder traversal Input/Output (I/O) 1-4, 14-2 See also I/O instance variable 9-17 Integer data type 3-12 interfaces 9-16, intermediate language code 1-8 interpreter 1-8 iteration 5-2 J Jacquard Loom 1-3 Just-In-Time compiler 1-8 L Label control adding to a form 2-36 setting properties 2-41 linked lists implementation operations literals 3-34 logical operators 4-6 loop 5-2 M machine language 1-6 Math class Max function member signatures Memory 1-4, 3-20 menubar 2-19, message boxes methods 1-9, definition how methods calls work naming conventions overloading See also procedures Microsoft Intermediate Language 2-6 Min function minimal class definition 11-4 modularity 1-9, 6-2 Module keyword 2-51 modulo operator 3-46 multi-dimensional arrays 7-32 assigning values 7-36 creation 7-33 declaration 7-33 ragged arrays 7-35 retrieving values 7-36 multiple aliases multiple If-statements 4-23 multiple inheritance 9-16 multiplication operator 3-42 MustInherit Keyword MyBase keyword N.NET 2-3.NET Framework 2-5.NET Framework Class Library 2-7, New operator 7-7, 10-8 Not operator 4-7 Nothing keyword null reference dereferencing problem Nothing keyword O object 1-9, 9-3 attributes 10-9 creation 10-8 initializing methods properties 10-9 variable declaration 10-7 Object class object equality object identity object-oriented programming 9-2 object-oriented programming languages 1-9 operand 3-4 operating system 2-3 operators 3-4 arithmetic operators 3-37 arithmetic/assignment operators 3-56 comparison operators 4-4 concatenation operators 8-9 logical operators 4-6 precedence 3-58 Or operator 4-7 OrElse operator 4-7 P panels parameters definition 6-7 I-3

17 Introduction to Programming with Microsoft Visual Basic.NET Index passed by reference 6-7 passed by value 6-7 passing to a procedure 6-8 polymorphism postorder traversal Pow function precedence of operators 3-58 preorder traversal primitive data types 3-11, 10-7 Private modifier 10-10, procedural programming languages 1-9 procedures Function procedure 6-9 See also methods Sub procedure 6-6 program 1-2 programming definition 1-2 history 1-3 steps for developing a program 1-11 programming languages event-driven programming languages 2-2 object-oriented programming languages 1-9 procedural programming languages 1-9 programming paradigm 1-9 programs Add2Numbers 3-2, 3-39 AddPrices 5-6 CompanyPayroll 6-3 CostCalculator 6-16 Divide2Numbers 3-45 InstallSoftware 4-15 LengthConverter 6-18 LowestPrice 7-25 Mod2Numbers 3-47 Multiply2Numbers 3-43 MultiWeatherData 4-24 PrintNumbers 5-16 PropagationDemo StudentInfo 7-27 Subtract2Numbers 3-41 TaxSalary 4-13 TheaterRow 7-18 TotalPrices 7-23 ToyProduction 5-12 WeatherData 4-11 WeatherOrNot 3-31 Weekdays 7-20 project 2-14 properties 11-6 Properties Window 2-22 Protected modifier 10-10, pseudocode 1-15 choosing between two alternative actions 1-17 choosing from multiple alternative actions 1-17 performing arithmetic 1-17 providing output 1-16 repeating actions 1-18 storing a value 1-17 taking input 1-16 Public modifier 10-10, Q queues 12-8 implementing using an array operations 12-9 R ragged arrays 7-35 Random Access Memory (RAM) 1-4 readers 14-3 recursion reference data types 3-11 reference to objects 10-7 repetition 4-2, 5-2 counter-controlled loops 5-3 Do-While loop 5-10 For loop 5-14 sentinel-controlled loops 5-3 While loop 5-4 reserved keywords 3-8 Return statement 6-9 S Select-Case statement 4-30 selection 4-2 If-statement without Else 4-14 If-Then-Else statement 4-9 multiple If-statements 4-23 Select-Case statement 4-30 sentinel-controlled loops 5-3 Set accessor 9-10, 11-7 Shared modifier short circuit evaluation 4-7 Sin function software maintenance 1-23 solution 2-14 Solution Explorer Window 2-22 Sqrt function stacks 12-3 implementing using an array 12-4 operations 12-4 Standard Toolbar 2-19 Startup object 2-43, statement 3-4 I-4

18 Introduction to Programming with Microsoft Visual Basic.NET Index Status Bar 2-19 stored program computers 1-3 StreamReader class 14-4 streams 14-2 StreamWriter class 14-5 String class methods 8-6 String data type 3-27 StringBuilder class 8-20 methods 8-22 Strings 3-27, 8-2 comparisons 8-15 concatenation 8-9 creation 8-2 immutability 8-5 printing 3-27 substrings 8-12 strongly typed languages 3-10 Sub procedure 2-51, 6-6 subclass 9-12 subtraction operator 3-40 superclass 9-12 syntax 3-6 T Throw statement Toolbox Window 2-19 try block 13-6 type casting 3-35 down-casting up-casting type conversion 3-35 U UML notation cardinality 9-31 cardinality symbols 9-33 class relationships 9-31 class-object relationship 9-29 inheritance relationships 9-35 single class 9-25 Unified Modeling Language (UML) 9-1 use case 15-2 Using a Shared Attribute V value data types 3-11 variables 3-5 assignment 3-7 declaration 3-6 local variables naming 3-8 Visual Basic.NET data types 3-11 development environment (IDE) 2-18 overview 2-2 types of programs 2-8 Visual Basic.NET Programming basic program structure 2-51 comments 2-53 compiling and running a program 2-23 creating a new project 2-34 event handling 2-43 filenames 2-30 laying out the GUI 2-34 opening a project 2-16 running a program from a DOS window 2-27, 2-30 setting form/control properties 2-39 steps for developing a program 2-31 Visual Studio.NET 2-4 configuring 2-15 launching 2-13 W weakly typed languages 3-10 Web applications 2-10 Web services 2-12 While loop 5-2, 5-4 Windows applications 2-9 Windows services 2-11 writers 14-3 Z Z3 1-3 I-5