Vb.net GPA计算

我很难找到计算GPA的正确代码。我尝试的每一件事都以错误的平均成绩告终。任何帮助都将不胜感激，我仍然是visual basic的初学者，但这是我能做的最好的了

Option Explicit On
Option Strict On
Option Infer Off

Public Class mainForm

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

  Private Sub dataButton_Click(sender As Object, e As EventArgs) Handles dataButton.Click

    Const Prompt As String = "Enter number of Credit Hours:"
    Const Title As String = "Credit Hours"
    Const Prompt2 As String = "Enter grade:"
    Const Title2 As String = "Grades"
    Dim inputCredit As String
    Dim inputGrades As String
    Dim creditHours As Integer
    Dim grades As Char
    Dim gradesCounter As Integer
    Dim point As Integer
    Dim gpaTotal As Double
    Dim creditHoursAccumulator As Integer
    Dim pointAccumulator As Integer


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

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


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

        pointAccumulator += 1
        gradesCounter += 1
        creditHoursAccumulator += creditHours


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


    Loop


    gpaTotal = pointAccumulator / creditHoursAccumulator
    totalCreditsLabel.Text = "Total credit hours:" & creditHoursAccumulator
    gpaLabel.Text = "GPA:" & gpaTotal
    totalGradesLabel.Text = "Number of grades entered:" & gradesCounter



End Sub
End Class

选项显式打开
选项严格限制在
选项推断
公共类主窗体
私有子exitButton\单击（发送者作为对象，e作为事件参数）处理exitButton。单击
我
端接头
私有子数据按钮单击（发送者作为对象，e作为事件参数）处理数据按钮。单击
Const Prompt As String=“输入学分数：”
常量标题为String=“学分”
Const Prompt2 As String=“输入等级：”
常量标题2为String=“Grades”
Dim inputCredit作为字符串
将输入变暗为字符串
将小时数设置为整数
暗度等级为半焦
作为整数的Dim Grades Center
变暗点为整数
Dim gpaTotal为双精度
Dim CreditHours作为整数的累加器
作为整数的Dim点累加器
inputCredit=InputBox（提示，标题）
inputGrades=输入框（Prompt2，标题2）
输入信用字符串时执行。空
整数.TryParse（inputCredit，creditHours）
字符TryParse（输入等级，等级）
选择个案职系
CChar案（“A”）
点=4
案件CChar（“B”）
点=3
CChar案（“C”）
点=2
CChar案（“D”）
点=1
案例CChar（“F”）
点=0
结束选择
点累加器+=1
坡度中心+=1
creditHoursAccumulator+=creditHours
inputCredit=InputBox（提示，标题）
inputGrades=输入框（Prompt2，标题2）
环
gpaTotal=点累加器/积分小时累加器
totalCreditsLabel.Text=“总学分：”&creditHoursAccumulator
gpaLabel.Text=“GPA:”&gpaTotal
totalGradesLabel.Text=“输入的分数：”&gradescenter
端接头
末级

不应使用以下行：

pointAccumulator += 1

是：

pointAccumulator += point