Array as structure members Assignment Student Test Scores - vb.net

Question

ASSIGNMENT
A teacher has six students and wants you to create an application that stores their grade data in a file and prints a grade report. The application should have a structure that stores the following student data: Name (a string), Test Scores (an array of five Doubles), and Average (a Double). Because the teacher has six students, the application should use an array of six structure variables.
The application should allow the user to enter data for each student, and calculate the average test score.
The user should be abled to save the data to a file, read the data from the file, and print a report showing each student's test scores and average score. The form shows a meny system. You may you buttons instead if you prefer.
Input validation: Do not accept test scores less that zero or greater than 100.
]
my understanding of how it should be structured
For the Moment I don't understand that in the FOR EACH loop I can not accumulate total it saying that I am not allowed to use + . I am trying to get scores from txtScore1Std1 (For example) assign it to dblTestScoreArray and using for each loop to find sum of those 5 score and when find average and output it to lbl average for student number 1.
Code Module:
Module StudentTestScoresModule
Const intMAX_SUBSCRIPT_STUDENT As Integer = 6
Const intMAX_SUBSCRIPT_STUDENT_SCORES As Integer = 5
'create structure
Public Structure StudentData
Dim strName As String
Dim dblTestScoresArray() As Double
Dim dblAverage As Double
End Structure
Dim dblTotalStd1 As Double
Dim dblScore As Double
Dim StudentsArray(intMAX_SUBSCRIPT_STUDENT) As StudentData
Sub StudentNameDataInput()
StudentsArray(0).strName = MainForm.txtStdName1.Text
StudentsArray(1).strName = MainForm.txtStdName2.Text
StudentsArray(2).strName = MainForm.txtStdName3.Text
StudentsArray(3).strName = MainForm.txtStdName4.Text
StudentsArray(4).strName = MainForm.txtStdName5.Text
StudentsArray(5).strName = MainForm.txtStdName6.Text
End Sub
Sub StudentScoreDataInput()
For intIndex = 0 To intMAX_SUBSCRIPT_STUDENT
ReDim StudentsArray(intIndex).dblTestScoresArray(4)
Next
'test scores for first student
StudentsArray(0).dblTestScoresArray(0) = CDbl(MainForm.txtScore1Std1.Text)
StudentsArray(1).dblTestScoresArray(1) = CDbl(MainForm.txtScore2Std1.Text)
StudentsArray(2).dblTestScoresArray(2) = CDbl(MainForm.txtScore3Std1.Text)
StudentsArray(3).dblTestScoresArray(3) = CDbl(MainForm.txtScore4Std1.Text)
StudentsArray(4).dblTestScoresArray(4) = CDbl(MainForm.txtScore5Std1.Text)
For Each i As StudentData In StudentsArray
dblTotalStd1 += i
Next
dblAverage = dblTotalStd1 / intMAX_SUBSCRIPT_STUDENT_SCORES
MainForm.lblAvgStd1.Text = (dblAverage.ToString)
End Sub
Sub CalculateAverage()
End Sub
End Module
Code Main Form:
Public Class MainForm
Private Sub mnuHelpAbout_Click(sender As Object, e As EventArgs) Handles mnuHelpAbout.Click
'about program
MessageBox.Show("Student test score calculator version 0.1")
End Sub
Private Sub btnExit_Click(sender As Object, e As EventArgs) Handles btnExit.Click
' Close(program)
Me.Close()
End Sub
Private Sub btnCalculate_Click(sender As Object, e As EventArgs) Handles btnCalculate.Click
StudentScoreDataInput()
End Sub
End Class

Answer 1

just by looking, without testing, what you need to do is;
'untested code
For Each i As StudentData In StudentsArray
For Each S as Double in i.dblTestScoresArray
dblTotalStd1 += s
Next
Next
you cannot do += on a structure, you need to do it on the member and since its an array, you need to loop through it