Week 1 – 3 Recap Useful links/info: TPITVB.blogspot.com

Useful links/info:

TPITVB.blogspot.com

VB.NET Week 1 Outline: Introduction Simple walk through Coding Conventions

Outline:

Introduction

Simple walk through

Coding Conventions

Coding Conventions All keywords – Start with Capital Example: Dim As Integer String Boolean If Then Else ElseIf End If Select Case Case End Select All variable name – Start with small letter Example: i x y nameOfVariable existingString total sumOfNumber

All keywords – Start with Capital

Example: Dim As Integer String Boolean

If Then Else ElseIf End If

Select Case Case End Select

All variable name – Start with small letter

Example: i x y nameOfVariable existingString

total sumOfNumber

VB.NET Week 2 Outline: Variables Strings Operators Maths helper functions Application: Create a Calculator for addition

Outline:

Variables

Strings

Operators

Maths helper functions

Application: Create a Calculator for addition

Variables - Declaring Declare a variable using the Dim and As keywords: Dim sumOfNumber As Integer Name of variable: sumOfNumber Type: Integer (Dim: Short for dimension)

Declare a variable using the Dim and As keywords:

Dim sumOfNumber As Integer

Name of variable: sumOfNumber

Type: Integer

(Dim: Short for dimension)

Variables - Declaring Data Type Summary Single: single-precision decimal (floating point) Double: double-precision decimal True, False Boolean 8 bytes to store date and time Date 8 bytes to store decimals (others: Single, Decimal) Double 4 bytes to store whole number (others: Short, Long) Integer word or sentence (for just one character: Char) String

Data Type Summary

Java 8 primitive types: b yte s hort i nt l ong f loat d ouble b oolean c har S tring – not primitive type

8 primitive types:

b yte

s hort

i nt

l ong

f loat

d ouble

b oolean

c har

S tring – not primitive type

Variables - assigning Assign a value to your variable with the = sign, which is sometimes called the assignment operator sumOfNumber = 42 This line of code takes the value 42 and stores it in the previously declared variable named sumOfNumber The equals sign is not actually an equals sign. The = sign here means assign a value of .

Assign a value to your variable with the = sign, which is sometimes called the assignment operator

sumOfNumber = 42

This line of code takes the value 42 and stores it in the previously declared variable named sumOfNumber

The equals sign is not actually an equals sign.

The = sign here means assign a value of .

Variables - assigning Declaring and Assigning Variables with a Default Value Dim sumOf Number As Integer = 0 Dim nameOfPerson As String = "None"

Declaring and Assigning Variables with a Default Value

Dim sumOf Number As Integer = 0

Dim nameOfPerson As String = "None"

Arithmetics Operators Division / Multiplication * Subtraction - Addition +

Other Arithmetic Operators ^ to the power of mod remainder after division (Java:%) division but return only integer portion Short cut: += x += y same as x = x + y -= x -= y same as x = x - y *= x *= y same as x = x * y /= x /= y same as x = x / y

^ to the power of

mod remainder after division (Java:%)

division but return only integer portion

Short cut:

+= x += y same as x = x + y

-= x -= y same as x = x - y

*= x *= y same as x = x * y

/= x /= y same as x = x / y

Do not have these operators Java ++ - -

Java

++

- -

Comparison Operators Comparison operators are used to in condition Eg If (condition) doSomthing 4 <> 4 (false) 4 <> 5 (true) 5 <> 4 (true) <> (not equal to) 4 = 4 (true) 4 = 5 (false) 5 = 4 (false) = (equals) Examples Operator

Comparison Operators 4 < 4 (false) 4 < 5 (true) 5 < 4 (false) < (less than) 4 > 4 (false) 4 > 5 (false) 5 > 4 (true) > (greater than) Examples Operator

Comparison Operators 4 <= 4 (true) 4 <= 5 (true) 5 <= 4 (false) <= (less than or equal to) 4 >= 4 (true) 4 >= 5 (false) 5 >= 4 (true) >= (greater than or equal to) Examples Operator

Conversion from String to other types Use CType if you are not sure the name of the conversion function Example: to convert to Boolean CType(variableName, Boolean)

Type Conversion examples Dim inputString As String = TextBox1.Text Dim x As Integer x = CInt (inputString) ' Convert to Integer. Dim y As Integer = 8 Textbox1.Text = CStr (y) ' Convert to String. c i n t c s t r

Dim inputString As String = TextBox1.Text

Dim x As Integer

x = CInt (inputString) ' Convert to Integer.

Dim y As Integer = 8

Textbox1.Text = CStr (y) ' Convert to String.

Maths Functions Math.Sqrt(n): Return the square root of n. Math.Abs(n): Return the absolute value of n. Math.Sign(n): Return the sign of n ( -1, 0 or +1 ). Example: Dim x As Integer Dim y As Integer = 25 TextBox1.Text = Math.Sqrt( y ) ‘ MsgBox( &quot;Sq root of 25 is &quot; & CStr(x) )

Math.Sqrt(n): Return the square root of n.

Math.Abs(n): Return the absolute value of n.

Math.Sign(n): Return the sign of n ( -1, 0 or +1 ).

Example:

Dim x As Integer

Dim y As Integer = 25

TextBox1.Text = Math.Sqrt( y )

‘ MsgBox( &quot;Sq root of 25 is &quot; & CStr(x) )

Class vs Local variables Public Class Form1 Dim x As Integer = 0 ' Class variables. Dim name As String = &quot;&quot; Sub Button0_Click … Dim y As Integer = 9 ' Local sub variables. End Sub : End Class x = 5 ' OK or Not? y = 5 ' OK or Not? x = 5 ' OK or Not? y = 5 ' OK or Not?

Public Class Form1

Dim x As Integer = 0 ' Class variables.

Dim name As String = &quot;&quot;

Sub Button0_Click …

Dim y As Integer = 9 ' Local sub variables.

End Sub

:

End Class

VB.NET lesson week Get Input from User If Then Else, Else If Select Case Add condition checking into Simple Calculator

Get Input from User

If Then Else, Else If

Select Case

Add condition checking into Simple Calculator

Get Input from User Dim name As String name = InputBox (&quot;Enter your name:&quot;) MsgBox (&quot;Your name is &quot; & name)

If Then Else, Else If Syntax If condition Then : End If Else : ElseIf condition2 Then ' Can repeat for : ' more conditions Example If name <> &quot;&quot; Then MsgBox(name) End If Example If name <> &quot;&quot; Then MsgBox(name) Else MsgBox(&quot;Empty&quot;) End If Example If name = &quot;&quot; Then MsgBox(&quot;Empty&quot;) ElseIf name = &quot;me&quot; Then MsgBox(&quot;Me&quot;) Else MsgBox(name) End If

Syntax

If condition Then

:

End If

More than one condition And condition1 And condition2 AndAlso condition1 AndAlso condition2 Recommended - Short-circuit And Eg If i > 0 AndAlso j <> 5 Then Once i > 0 is false, no need to check j <> 5

And condition1 And condition2

AndAlso condition1 AndAlso condition2

Recommended - Short-circuit And

Eg If i > 0 AndAlso j <> 5 Then

More than one condition Or condition1 Or condition2 OrElse condition1 OrElse condition2 Recommended - Short-circuit Or Eg If i > 0 OrAlso j <> 5 Then Once i > 0 is true, no need to check j <> 5

Or condition1 Or condition2

OrElse condition1 OrElse condition2

Recommended - Short-circuit Or

Eg If i > 0 OrAlso j <> 5 Then

Short cut If and Assignment IIf I mmediate If x = IIf( i > 0, 1, 0) Same As If i > 0 Then x = 1 Else x = 0 End If

IIf I mmediate If

x = IIf( i > 0, 1, 0)

Same As

If i > 0 Then

x = 1

Else

x = 0

End If

Select Case Syntax Select Case variable Case condition1 : Case condition2 : Case Else : End Select Example Select Case name Case &quot;&quot; MsgBox(&quot;Empty&quot;) Case &quot;Me&quot; MsgBox(&quot;me&quot;) Case Else MsgBox(name) End Select

Syntax

Select Case variable

Case condition1

:

Case condition2

:

Case Else

:

End Select

Select Case Conditions Case &quot;red&quot;, &quot;white&quot;, &quot;green&quot; ' A few together . Case 1 To 10 ' A range using ' keyword To . Case Is > 9 ' A range using ' keyword Is .

Case &quot;red&quot;, &quot;white&quot;, &quot;green&quot; ' A few together .

Case 1 To 10 ' A range using

' keyword To .

Case Is > 9 ' A range using

' keyword Is .

Java if (condition) { : } else if (condition 2) { } else { : } switch variable { case 1: : break; case 2: : break; default: : }

if (condition) {

:

} else if (condition 2) {

} else {

:

}

End of lessons