Static Variables for Grade Counting Program [modified] - SOLVED

[Adam Wike]

My teacher want's me to design a program that does this. "Design a program that has five buttons, one for each grade. Each time you press a button it increments that grade by one. At the same time it updates a label that displays the current percent of students that passed the exam (grade higher than F)." This is what I have so far...

Public Class Form1

Private Sub btnA\_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnA.Click
    Static intA As Integer = 0
    intA = intA + 1
    lblGradea.Text = intA
End Sub

Private Sub btnB\_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnB.Click
    Static intB As Integer = 0
    intB = intB + 1
    lblGradeb.Text = intB
End Sub

Private Sub btnC\_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnC.Click
    Static intC As Integer = 0
    intC = intC + 1
    lblGradec.Text = intC
End Sub

Private Sub btnD\_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnD.Click
    Static intD As Integer = 0
    intD = intD + 1
    lblGraded.Text = intD
End Sub

Private Sub btnF\_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnF.Click
    Static intF As Integer = 0
    intF = intF + 1
    lblGradef.Text = intF
End Sub

End Class

I need help on that part that displays what percentage of students are passing. I assume you have to add together the toal number of grades and then divide by the total number above F and display that in a label. But I cant seem to figure that out...Thanks :-D

modified on Tuesday, March 30, 2010 10:18 AM

[Estys]

My interpretation of the problem is that every time you press a button, the number of students with that particular grade is incremented. That means that your result must be sum(intA to intE)/ sum(intA to intF).

[Steven J Jowett]

I don't normally do student's homework, but seeing as you have attempted to solve the problem here is some pointers... Remove the lines that declare the STATIC integer and make the PRIVATE member variables e.g.

Public Class Form1
Private intA As Integer
Private intB as Integer
Private intC as Integer
Private intD as Integer
Private intF as Integer

In the Form_Load Event handler, initiate the starting values e.g.

intA = 0
intB = 0

Now all you need is a Function to return the averages.

Steve Jowett ------------------------- Real programmers don't comment their code. If it was hard to write, it should be hard to read.

[Adam Wike]

I figured it out :) Thank you both for steering me in the right direction. Not sure if its the most effcient way of making the program but it does what it's supposed to. Here is the final code...

'Adam Wike
'Computer Programming 1
'Grade Counter
'Created on March 28, 2010
'Last Modified on March 30, 2010

Public Class Form1

'Declared all variables
Private intA As Integer
Private intB As Integer
Private intC As Integer
Private intD As Integer
Private intF As Integer
Private intE As Integer

'Sets the variables to 0
Private Sub Form1\_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
    intA = 0
    intB = 0
    intC = 0
    intD = 0
    intF = 0
End Sub

'Sets up the counter and calculates the percentage for each button
Private Sub btnA\_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnA.Click
    intA = intA + 1
    lblGradea.Text = intA
    intE = ((intA + intB + intC + intD) / (intA + intB + intC + intD + intF)) \* 100
    lblPassing.Text = Math.Round(intE, 2) & "%"
End Sub

Private Sub btnB\_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnB.Click
    intB = intB + 1
    lblGradeb.Text = intB
    intE = ((intA + intB + intC + intD) / (intA + intB + intC + intD + intF)) \* 100
    lblPassing.Text = Math.Round(intE, 2) & "%"
End Sub

Private Sub btnC\_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnC.Click
    intC = intC + 1
    lblGradec.Text = intC
    intE = ((intA + intB + intC + intD) / (intA + intB + intC + intD + intF)) \* 100
    lblPassing.Text = Math.Round(intE, 2) & "%"
End Sub

Private Sub btnD\_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnD.Click
    intD = intD + 1
    lblGraded.Text = intD
    intE = ((intA + intB + intC + intD) / (intA + intB + intC + intD + intF)) \* 100
    lblPassing.Text = Math.Round(intE, 2) & "%"
End Sub

Private Sub btnF\_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnF.Click
    intF = intF + 1
    lblGradef.Text = intF
    intE = ((intA + intB + intC + intD) / (intA + intB + intC + intD + intF)) \* 100
    lblPassing.Text = Math.Round(intE, 2) & "%"
End Sub

End Class

[Steven J Jowett]

adamwike wrote:

intE = ((intA + intB + intC + intD) / (intA + intB + intC + intD + intF)) * 100 lblPassing.Text = Math.Round(intE, 2) & "%"

The above should not be repeated in every button click event. Consider making in a sub-routine for example :

Private Sub CalcIntE()
intE = ((intA + intB + intC + intD) / (intA + intB + intC + intD + intF)) * 100
lblPassing.Text = Math.Round(intE, 2) & "%"
End Sub

Then replace the necessary code in each button click event with CalcIntE for example

Private Sub btnA_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BtnA.Click
intA = intA + 1
lblGradea.Text = intA
CalcIntE
End Sub

Steve Jowett ------------------------- Real programmers don't comment their code. If it was hard to write, it should be hard to read.

[Adam Wike]

Your right, that is a lot less confusing and makes the program look less cluttered. Thanks!

[Steven J Jowett]

adamwike wrote:

that is a lot less confusing and makes the program look less cluttered

Not only that, but more importantly, it is more maintainable.

Steve Jowett ------------------------- Real programmers don't comment their code. If it was hard to write, it should be hard to read.