Help With Functions Project

[Pompy]

Hi im trying to do this project for class on functions. I am little confused on what i am doing wrong.

Here is the assignment

1) Write a program to calculate the wind chill. The wind chill is calculated by using the ambient temperature and the wind speed.

Wind chill temp = 91.4 + (temp - 91.4)(.474 + .304 sqrt(Wind Speed) - .0203(wind speed))

2) write a program to convert a numerical grade to a letter grade.

below 70 -F
70-79 - C
80-89 - B
90-100 - A

Here is the form




Here is the code

Public Class Form1

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Dim IntTemp, IntWS As Integer
        IntTemp = Val(TextBox1.Text)
        IntWS = Val(TextBox2.Text)
        Label1.Text = WindChill(IntTemp, IntWS)
    End Sub
        Function WindChill(ByVal Temp As Double, ByVal Wspeed As Double) As Double
        Return 91.4 + (Temp - 91.4)(0.474 + 0.304Sqrt(Wspeed) - 0.0203(Wspeed))
    End Function


    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
        Dim grade As Integer
        grade = TextBox1.Text
        Label3.Text = Lettergrade(grade)
    End Sub

    Function Lettergrade(ByVal Numgrade As Integer) As Char
        If Numgrade < 70 Then
            Label3.Text = "F"
        ElseIf Numgrade < 79 Then
            Label3.Text = "C"
        ElseIf Numgrade < 89 Then
            Label3.Text = "B"
        ElseIf Numgrade < 100 Then
            Label3.Text = "A"
        End If
    End Function


End Class

Thanks for the help. I know there is something wrong with my code, just dont know how to fix it.

[passel]

You can't copy the equation directly as stated. You have to convert it to code.
0.203(Wspeed) is multiplication in the instructions, but it is not multiplication in code.
0.203 * Wspeed is multiplication in code. You need the * operator for multiplication.
(x - y) (a + b) indicates multiplication of the two expressions in the instructions, but is not multiplication in code.
(x - y) * (a + b) To multiply the two expressions.

Sqrt is a method (function) of the Math class. You have to either say Math.Sqrt(x) or do an Imports Math at the top of the file to bring the Math namespace into scope so you don't have to put Math.xxxx on every function.

[Gruff]

Have you tried stepping through your code in debug mode one line at a time?
doing so and examining each variable should show you the problem.

Ah! you slipped in there Passel!

[passel]

Yeah. He can't step through the code until he can compile it.

[Pompy]

Thanks i fixed the first assignment!!

I still cant get the 2nd assignment. When i try to debug it says Function lettergrade doesnt return a value on all code paths. Are you missing a return statement?

I dont know what that means.

[Gruff]

There are two types of procedures in VB. Sub Routines and Functions.
Functions should return a single value or object. Sub Routines do not.

In VB.NET you should use the 'Returns' keyword with a value you want returned.

Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
  Dim Answer as integer = 21
  Answer = AddTwo(Answer)
  MessageBox.Show(Answer.Tostring)
  'Will show 23.
End Sub

Public Function AddTwo(Input as integer) as Integer
  Dim Total as integer = Input + 2
  Return Total
End Function

In short you are mis-using a function.
you are not returning anything from inside your function.