Variables and Constants

Variables

• How to create a variable and assign it a value.
• How to use a value stored in a variable.
• What are the different types of values that we can store in a computer program?

We are going to edit our Payroll program to store the hours, hourly pay and total pay in variables.

Examples of Declaring Variables:

Make sure to give variables meaningful names, and use the proper prefix for the type of data that they will store.

Ex. 1 - Storing Numbers with no Decimals

Dim intAge as Integer                                    'Declare the variable 

intAge = 15                                              'Assign a value to the variable

lblOutput.Text = "You are " & intAge & " years old!"     'Use variable

Ex. 2 - Storing Numbers with Decimals

Dim dblPrice as Double                 'Declares variables that can store decimal numbers

Dim dblTax as Double

Dim dblTotal as Double

dblPrice = 10.99                        'Assigns values to dblPrice and dblTax

dblTax = 1.13

dblTotal = dblTax * dblPrice            'Calculates final price

lblTotalPrice.Text = "$" & dblTotal     'Outputs final price with '$' in front

Ex. 3 - Storing Words/Characters/Numbers as Text

Dim strName as String                         'Declare variable that can store words

strName = "Mr. Aldworth"                      'Assign a value to variable using " "

lblGreeting.Text = "Welcome " & strName       'Use variable to output a nice greeting

Formatting Numbers

• We often want to control the look of the numbers that we display in our programs. We can round our numbers, and automatically format them as currency amounts (very handy)

We are going to edit our Payroll program to display our monetary values as properly formatted currency.

If you finish, attempt the VB Color Application for bonus marks.