1. Function

2. The Wind Chill Project
Write a program that calculates the wind chill temperature
Find a formula - UST Today Weather Web site
Inputs: Wind Speed and Temperature
Outputs: Wind Chill Temperature

3. The Wind Chill Project Orginal formula Visual Basic statement
WC = (3.71(V **0.5) V)(T )
Visual Basic statement
WC = * (3.71 * Sqr(V) (0.25 * V)) * (T )

4. Functions Function - unit of code that returns a value
Build-in Functions
Sqr - square root
Rnd - random number generator
Int - returns integer portion of a number
Val - converts a string to a value

5. Functions Locating built-in functions Programmer-written functions
Open the Functions online reference book or search for a function by name
Programmer-written functions
Write your own functions using the Function statement

6. The Function Statement
Private Function function-name (argument1, argument2....)
statements
End Function
Where
Private or Public is required
Function indicates the beginning of a function
function-name is the name that will be used to call the function
( ) parentheses are required around the argument list
argument1, argument2 are optional variables needed to perform
the calculation or actions needed for the function
End Function indicates the end of the function

7. WindChill Function Private Function WindChill( )
‘Purpose: Calculate the Wind Chill
‘Reference: National Weather Service
Dim V As Integer ‘Wind Speed Velocity
Dim T AS Integer ‘Temperature
V = hsbSpeed.Value
T = hsbTemperature.Value
WindChill = * (3.71 * Sqr(V) _
(0.25*V)) * (T-91.4)+91.4
End Function

8. WindChill Function Private Sub cmdCalculate_Click() WC = WindChill()
When the cmdCalculate button is clicked, the WindChill function is executed
Private Sub cmdCalculate_Click()
WC = WindChill()
txtWindChill.Text = Cint(WC)
End Sub

9. The Wind Chill Project using Functions and Procedures
Hands-On Exercise 1 (p )
Create a New Project
Create the Controls for Temperature Input
Create the Controls for Wind Speed Input
Create the Controls for Wind Chill Output
Create the Image Control
Add Banner Comments
Add the Wind Chill Function
Add Temperature and Speed Procedures
Save, Run, Test your Project

10. End of Lecture