Condition

If Block

Decisions based on conditions:

If (condition) Then

action 1 

Else

action 2   (or error message)

Select Case Block

Decision of One Variabl

Select Case Shapes

     Case "Circle"

          number = 1

     Case "Square"

         number = 2

Select Case with numbers

Select Case totalsales

Case Is <= 400

     tax = 400 * .05

Case Is <= 500

    tax = 500 * .05 + 2

Relational Operators

<, >, =, <>, <=, >=, 

Principal Logical Operators

And, Or, Not

Boolean Data Type

Any variable or expression that evaluates to either true or false. 

Sub Procedure

A part of a program that performs one of more related tasks, has its own name, and is written as a separate part of the program.  

Sub procedure example

Call CalculateDensity("Hawaii, 1263244)

Sub CalculateDensity(ByVal state As String, ByVal pop As Double....)

End Sub

Modular or Top-Down Design

By Value

ByVal:

when a variable is passed to a parameter so that it receives only a copy.

ByReference

ByRef:

When a variable is passed by reference as in the parameter sends a location and only has a "thread" to the call statement it corresponds with.

Function Procedures

User-defined functions

A general procedure that returns a single value.  

Example of Function

Function CalcRectangle(ByVal length As Double, ByVal width As Double)

Return length * width

End Function

Arguments and Parameters

In any procedure, the arguments in the calling statement must match the parameters in the procedure in number, type and order.  They do not need to match in name. 

Substring

.Substring returns a word or letters

"fanatic".Substring(0,3)  is "fan"

IndexOf

IndexOf returns a position number

"fanatic".IndexOf("ati")  is 3

Example of Zones

Dim fmtZone As String = "{0,-10}{1,12}"

lstResults.Items.Add(String.Format(fmtZone, "College", "City", "Students")

lstResults.Items.Add(String.Format(fmtZone, "Mizzou", "Columbia", 15000)