CODEWITHSUNDEEP
vb.netcalculator
user1623330
user1623330

Reputation: 1

Problems in creating GPA calculator in visual basic

Public Class GPA_Form

Private Sub exitButton_Click(sender As System.Object, e As System.EventArgs) Handles exitButton.Click
    Me.Close()
End Sub

Private Sub entdatButton_Click(sender As System.Object, e As System.EventArgs) Handles entdatButton.Click
    Const Prompt As String = "Enter number of Credit Hours:"
    Const Title As String = "Credit Hours"
    Const Prompt2 As String = "Enter grades:"
    Const Title2 As String = "Grades"
    Dim inputCredit As String
    Dim inputGrades As String
    Dim creditHrs As Integer
    Dim grades As Char
    Dim gradesCounter As Integer
    Dim creditHrsAccumulator As Integer
    Dim point As Integer
    Dim gpaTot As Integer
    Dim pntAccumulator As Integer

    inputCredit = InputBox(Prompt, Title)
    inputGrades = InputBox(Prompt2, Title2)

    Do While inputCredit <> String.Empty
        Integer.TryParse(inputCredit, creditHrs)
        Char.TryParse(inputGrades, grades)

        gradesCounter += 1
        creditHrsAccumulator += creditHrs

        Select Case grades
            Case Is >= "A"
                point = 4
            Case Is >= "B"
                point = 3
            Case Is >= "C"
                point = 2
            Case Is >= "D"
                point = 1
            Case Is >= "F"
                point = 0
        End Select

        pntAccumulator += point

        gpaTot = pntAccumulator / gradesCounter

        tchData.Text = creditHrsAccumulator.ToString("N0")
        numGrEnt.Text = gradesCounter.ToString("N0")
        gpaData.Text = gpaTot.ToString("N2")

        inputCredit = InputBox(Prompt, Title)
        inputGrades = InputBox(Prompt2, Title2)

    Loop


End Sub
End Class

I'm just a beginner in visual basic but would like to know where I'm going wrong here in calculating GPA and even if accumulating something from Select...Case is possible. If not then I would have to type this in differently then shown above, of course. If anyone can give me hints as to what I'm doing wrong it would be greatly appreciated.

Upvotes: 0

Views: 5483

Answers (3)

Peter
Peter

Reputation: 1

when comparing a string you cant use >= you are saying if grade is greater than or equal to a string, where it can only be equal too or not equal too.

<= pr >= only works with comparing numbers.

Upvotes: 0

John Alexiou
John Alexiou

Reputation: 29254

The GPA formula is not gpaTot = pntAccumulator / gradesCounter but

gpaTot = 0
creditHrsAccumulator = 0

Do While inputCredit <> String.Empty
    Integer.TryParse(inputCredit, creditHrs)
    Char.TryParse(inputGrades, grades)

    Select Case grades
        Case "A"
            point = 4
        Case "B"
            point = 3
        Case "C"
            point = 2
        Case "D"
            point = 1
        Case "F"
            point = 0
    End Select

    gpaTot= (creditHrsAccumulator*gpaTot + point*creditHrs)/(creditHrsAccumulator + creditHrs)
    gradesCounter += 1
    creditHrsAccumulator += creditHrs

    ...

And you can get rid of the pntAccumulator.

Upvotes: 1

MPelletier
MPelletier

Reputation: 16697

Select ... Case is formatted differently from what you used.

We all know that for grades, A > B > C, but Visual Basic doesn't know that. In Visual Basic, these are just chars, and they are not comparable thus. A Case statement does not support comparison operators like >=, they are implicitly ==, and you don't write "Case Is", just "Case". Try this:

Select Case grades
    Case "A"
        point = 4
    Case "B"
        point = 3
    Case "C"
        point = 2
    Case "D"
        point = 1
    Case "F"
        point = 0
End Select

Upvotes: 1

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