(c) Bob McKillop, 2006Tutorial #1 T1-1 Tutorial #1 - your first compiled code the learning objectives for this tutorial are very modest q compile and

(c) Bob McKillop, 2006

Tutorial #1

T1-1Tutorial #1 - your first compiled code

the learning objectives for this tutorial are very modest compile and execute three VB.NET console applications on the

NEXUS system program 1 – Hello World! program 2 – obtaining the user’s name from the console program 3 – computing the real roots of a quadratic equation

the purpose of the tutorial is to provide practice writing, compiling and executing simple code snippets.

you are NOT expected to understand anything that you you are NOT expected to understand anything that you

type!type!

Assignment #1Assignment #1

each student is asked modify program #3 and submit an improved version of program #3 before noon on Friday.


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using the Windows Start Menu, select:

>>All Programs

>>Programming

>>Microsoft Visual Studio.NET 2003

>>Visual Studio. NET Tools

>> Visual Studio .NET 2003 Command Prompt


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your screen should now display the Visual Studio .NET Command Prompt

your prompt should indicate that you are presently working on the N: drive

if not, type n:n: and hit the Enter key


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type vbcvbc and hit the Enter key

your screen should now include a listing of the Visual Basic compiler options

it is not as scary as it looks. We will be using only a few of the compiler options.


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type clscls to clear the screen display

let’s make a working directory (folder) on your n: drive

type md cive121md cive121 and hit the Enter key.

type cd cive121cd cive121 and hit the Enter key

type dirdir and hit the Enter key. The display should list the contents of your newly created directory (folder). In our case, there should be no files located within the directory…yet


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T1-6Program #1

you will need a code editor for this course there are plenty of free code editors available on the web (NotePad2,

EditPad Lite, etc.) for today, use the default NotePadNotePad editor provided with Windows. From the

Windows Start Menu, choose:

>>All programs

>>Accessories

>>NotePad open the text editor and carefully enter the following code

save your untitled document as hello.vbhello.vb and be sure to save it in the cive121cive121 directory


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at the command prompt, type dirdir and hit the Enter key. You should now see your newly created text file name hello.vbhello.vb within the directory listing

type vbc hello.vbvbc hello.vb and hit the Enter key. Hopefully, your program compiles successfully.

at the command prompt, type dirdir and hit the Enter key. You should now see your newly created

hello.exehello.exe executable


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at the command prompt, type hellohello (or hello.exehello.exe) and hit the Enter key.

you should now see the message Hello World!Hello World! displayed on your console

congratulations, you have successfully created, compiled and executed your first VB.NET program!


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T1-9Commenting your code

It is important to appreciate this simple fact…a computer program is to be executed by a computer but it will be read by other people

large programs may involve dozens if not hundreds of programmers

most programs undergo:• significant modification and/or upgrading• fixing bugs/errors

it is important to comment our code in order for other people to understand how our program works, today or several years from now.

in many cases, a programmer will revisit his/her own program after several months ors year and it is easy to forget some of the important details about your own code

in VB.NET, the compiler ignores any instructions located to the right of an apostrophe (`̀)


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comment your previous code as follows.

‘ ‘ ========================================================================================================================================================

‘ ‘ Program #1Program #1

‘ ‘ Written by: Bob McKillopWritten by: Bob McKillop

‘ ‘ Date: January 03, 2006Date: January 03, 2006

‘ ‘ ========================================================================================================================================================

Option Strict On ‘ impose strict type checking‘ impose strict type checking

Imports System ‘ import system namespace‘ import system namespace

Module MyFirstProgram

Public Sub Main()

Console.WriteLine("Hello World!") ‘ direct output stream to ‘ direct output stream to

‘ ‘ the consolethe console

End Sub

End Module

compile and execute your program and observe the program output


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T1-11Program #2

program #1 provided an easy introduction to compiling and executing a VB program but…the program did not accept any input and it did not make use of any variables (data)

save your hello.vbhello.vb program as intro.vbintro.vb

we will now modify the previous program in order to prompt the user for his/her first name

the program will then offer an introductory greeting to the user as illustrated below:


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enter the following code. Compile and execute the program. When prompted, type in your name and hit the <Enter> key.

‘ ‘ ========================================================================================================================================================‘ ‘ Program #2Program #2‘ ‘ Written by: Bob McKillopWritten by: Bob McKillop‘ ‘ Date: January 03, 2006Date: January 03, 2006‘ ‘ ‘ ‘ Modified: January 03, 2006 by Bob McKillopModified: January 03, 2006 by Bob McKillop‘ ‘ Added ReadLine method in order to obtain users first nameAdded ReadLine method in order to obtain users first name‘ ‘ from the Console from the Console ‘ ‘ ========================================================================================================================================================Option Strict On ‘ impose strict type checking‘ impose strict type checkingImports System ‘ import System namespace‘ import System namespaceImports System.IOImports System.IO ‘ import System.IO namespace‘ import System.IO namespaceModule Program_02 Public Sub Main() Console.WriteLine()Console.WriteLine() Dim name As String ‘ Declare String objectDim name As String ‘ Declare String object Console.Write("Please type your first name: ")Console.Write("Please type your first name: ") name = Console.ReadLine() ‘ Obtain input stream name = Console.ReadLine() ‘ Obtain input stream Console.WriteLine()Console.WriteLine() Console.WriteLine ("Hello " & name)Console.WriteLine ("Hello " & name) Console.WriteLine ("Welcome to the course!")Console.WriteLine ("Welcome to the course!") End SubEnd Module


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T1-13Program #3

save your intro.vbintro.vb program as quadratic.vbquadratic.vb our previous programs did not perform any computations and program #2

made use of a single String type. let’s write a program capable of computing the roots of an expression of the

form:

recall that the closed-form solution is given by:

for this problem, assume that real roots always exist test your program using

a = 1 b = 3, and c = -18

a

acbbx

2

42

02 cbxax


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enter the following code. Compile and execute the program. ' ==========================================================================' ==========================================================================' Program #3 ' Program #3 ' Written By: Bob McKillop' Written By: Bob McKillop' Date: January 03, 2006' Date: January 03, 2006' Purpose To compute quadratic roots' Purpose To compute quadratic roots' Inputs Constants a, b and c' Inputs Constants a, b and c' Outputs The 2 real roots ' Outputs The 2 real roots ' Limitations This program does not check for the existence of' Limitations This program does not check for the existence of' non-existing or complex roots ' non-existing or complex roots ' ==========================================================================' ==========================================================================Option Strict OnImports SystemImports System.Math 'Import System.Math namespace'Import System.Math namespaceModule Program_03 Public Sub Main() Dim a As Double = 1 Dim b As Double = 3 Dim c As Double = -18 Dim root1, root2 As Double Dim term As Double term = b ^ 2 - 4 * a * c root1 = (-b + Sqrt(term)) / (2 * a) root2 = (-b - Sqrt(term)) / (2 * a) Console.WriteLine ("The first root is {0,6:F2}", root1) Console.WriteLine ("The second root is {0,5:F2}", root2) End SubEnd Module


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T1-15Assignment #1

Modify program #3 in order for the following output to be exactly produced:

Before Friday January 06Friday January 06 (at noon), submit to the WEEF assignment box:

a listing of your program code. Make sure your code includes a fully

completed and signed program header, available on the course web site

(see page 3-9 of the course notes for more details). If you are having

difficulty with console output, refer to some of the example code

provided in Chapter 5 of the course notes.

a screen capture illustrating your program output

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(c) Bob McKillop, 2006Tutorial #1 T1-1 Tutorial #1 - your first compiled code the learning objectives for this tutorial are very modest q compile and