Visual Basic-如何从测试用例中调用函数并为数组返回值

Question

Yes - this if for a version of the "household survey" problem. I'm trying to understand one specific part not get the answer for the whole problem! I have a "select case true" to load information into my arrays, and one of the arrays is used to determine if a household meets poverty requirements or not. I am using a subroutine to run a second select case to determine if the household meets the criteria and if it does add that to an array. This code works but it is spaghetti code - how can I create one test case that works for all the counties instead of using one for each as below?

'subroutine to load data to arrays, reset the form and call a new random ID number
Private Sub SubmitData()
    Dim intHouseHoldIncome As Integer = CInt(txtHouseholdIncome.Text)

    'as per the county and state , store values in array
    Select Case True
        Case cbxCountyState.Text = "Hamilton,OH"
            income(0) = income(0) + intHouseHoldIncome
            count(0) = count(0) + 1
            Call povertystatus_0()
        Case cbxCountyState.Text = "Butler,OH"
            income(1) = income(1) + intHouseHoldIncome
            count(1) = count(1) + 1
            Call povertystatus_1()
        Case cbxCountyState.Text = "Clermont,OH"
            income(2) = income(2) + intHouseHoldIncome
            count(2) = count(2) + 1
            Call povertystatus_2()
        Case cbxCountyState.Text = "Warren,OH"
            income(3) = income(3) + intHouseHoldIncome
            count(3) = count(3) + 1
            Call povertystatus_3()
        Case cbxCountyState.Text = "Campbell,KY"
            income(4) = income(4) + intHouseHoldIncome
            count(4) = count(4) + 1
            Call povertystatus_4()
        Case cbxCountyState.Text = "Boone,KY"
            income(5) = income(5) + intHouseHoldIncome
            count(5) = count(5) + 1
            Call povertystatus_5()
        Case cbxCountyState.Text = "Kenton,KY"
            income(6) = income(6) + intHouseHoldIncome
            count(6) = count(6) + 1
            Call povertystatus_6()
    End Select
    'Clear and re-focus inputs
    lblIdNumber.Text = ""
    cbxHouseholdSize.SelectedIndex = -1
    cbxCountyState.SelectedIndex = -1
    txtHouseholdIncome.Text = String.Empty
    'call random function to provide new id number
    Call IdNumber()
End Sub

'function to determine poverty status+++++++++++++++++++
Private Sub povertystatus_0()
    Dim intHouseHoldIncome As Integer = CInt(txtHouseholdIncome.Text)
    Dim intsize As Integer = CInt(cbxHouseholdSize.SelectedItem)
    Dim testincome As Integer
    Select Case intsize
        Case 1
            testincome = 10210
        Case 2
            testincome = 13690
        Case 3
            testincome = 17170
        Case 4
            testincome = 20650
        Case 5
            testincome = 24130
    End Select
    If intHouseHoldIncome <= testincome Then
        povertytrue(0) = povertytrue(0) + 1
    End If
End Sub

Private Sub povertystatus_1()
    Dim intHouseHoldIncome As Integer = CInt(txtHouseholdIncome.Text)
    Dim intsize As Integer = CInt(cbxHouseholdSize.SelectedItem)
    Dim testincome As Integer
    Select Case intsize
        Case 1
            testincome = 10210
        Case 2
            testincome = 13690
        Case 3
            testincome = 17170
        Case 4
            testincome = 20650
        Case 5
            testincome = 24130
    End Select
    If intHouseHoldIncome <= testincome Then
        povertytrue(1) = povertytrue(1) + 1
    End If
End Sub

Private Sub povertystatus_2()
    Dim intHouseHoldIncome As Integer = CInt(txtHouseholdIncome.Text)
    Dim intsize As Integer = CInt(cbxHouseholdSize.SelectedItem)
    Dim testincome As Integer
    Select Case intsize
        Case 1
            testincome = 10210
        Case 2
            testincome = 13690
        Case 3
            testincome = 17170
        Case 4
            testincome = 20650
        Case 5
            testincome = 24130
    End Select
    If intHouseHoldIncome <= testincome Then
        povertytrue(2) = povertytrue(2) + 1
    End If
End Sub

Private Sub povertystatus_3()
    Dim intHouseHoldIncome As Integer = CInt(txtHouseholdIncome.Text)
    Dim intsize As Integer = CInt(cbxHouseholdSize.SelectedItem)
    Dim testincome As Integer
    Select Case intsize
        Case 1
            testincome = 10210
        Case 2
            testincome = 13690
        Case 3
            testincome = 17170
        Case 4
            testincome = 20650
        Case 5
            testincome = 24130
    End Select
    If intHouseHoldIncome <= testincome Then
        povertytrue(3) = povertytrue(3) + 1
    End If
End Sub

Private Sub povertystatus_4()
    Dim intHouseHoldIncome As Integer = CInt(txtHouseholdIncome.Text)
    Dim intsize As Integer = CInt(cbxHouseholdSize.SelectedItem)
    Dim testincome As Integer
    Select Case intsize
        Case 1
            testincome = 10210
        Case 2
            testincome = 13690
        Case 3
            testincome = 17170
        Case 4
            testincome = 20650
        Case 5
            testincome = 24130
    End Select
    If intHouseHoldIncome <= testincome Then
        povertytrue(4) = povertytrue(4) + 1
    End If
End Sub

Private Sub povertystatus_5()
    Dim intHouseHoldIncome As Integer = CInt(txtHouseholdIncome.Text)
    Dim intsize As Integer = CInt(cbxHouseholdSize.SelectedItem)
    Dim testincome As Integer
    Select Case intsize
        Case 1
            testincome = 10210
        Case 2
            testincome = 13690
        Case 3
            testincome = 17170
        Case 4
            testincome = 20650
        Case 5
            testincome = 24130
    End Select
    If intHouseHoldIncome <= testincome Then
        povertytrue(5) = povertytrue(5) + 1
    End If
End Sub

Private Sub povertystatus_6()
    Dim intHouseHoldIncome As Integer = CInt(txtHouseholdIncome.Text)
    Dim intsize As Integer = CInt(cbxHouseholdSize.SelectedItem)
    Dim testincome As Integer
    Select Case intsize
        Case 1
            testincome = 10210
        Case 2
            testincome = 13690
        Case 3
            testincome = 17170
        Case 4
            testincome = 20650
        Case 5
            testincome = 24130
    End Select
    If intHouseHoldIncome <= testincome Then
        povertytrue(6) = povertytrue(6) + 1
    End If
End Sub

Answer 1

It's not spaghetti code. It just contains A LOT of repetition. You are flagrantly violating the DRY principle, ie don't repeat yourself.

As far as I can tell, each of your povertystatus methods is exactly the same except for the array index so, as is always the rule in such cases, extract that index out as a parameter and collapse all those methods into one:

Private Sub PovertyStatus(index As Integer)
    Dim intHouseHoldIncome As Integer = CInt(txtHouseholdIncome.Text)
    Dim intSize As Integer = CInt(cbxHouseholdSize.SelectedItem)
    Dim testIncome As Integer

    Select Case intSize
        Case 1
            testIncome = 10210
        Case 2
            testIncome = 13690
        Case 3
            testIncome = 17170
        Case 4
            testIncome = 20650
        Case 5
            testIncome = 24130
    End Select

    If intHouseHoldIncome <= testIncome Then
        povertyTrue(index) = povertyTrue(index) + 1
    End If
End Sub

Note that I've also changed the casing of various names there to be consistent.

You can then fix your first Select Case monstrosity too. This:

Select Case True
    Case cbxCountyState.Text = "Hamilton,OH"
        income(0) = income(0) + intHouseHoldIncome
        count(0) = count(0) + 1
        Call povertystatus_0()
    Case cbxCountyState.Text = "Butler,OH"
        income(1) = income(1) + intHouseHoldIncome
        count(1) = count(1) + 1
        Call povertystatus_1()
    Case cbxCountyState.Text = "Clermont,OH"
        income(2) = income(2) + intHouseHoldIncome
        count(2) = count(2) + 1
        Call povertystatus_2()
    Case cbxCountyState.Text = "Warren,OH"
        income(3) = income(3) + intHouseHoldIncome
        count(3) = count(3) + 1
        Call povertystatus_3()
    Case cbxCountyState.Text = "Campbell,KY"
        income(4) = income(4) + intHouseHoldIncome
        count(4) = count(4) + 1
        Call povertystatus_4()
    Case cbxCountyState.Text = "Boone,KY"
        income(5) = income(5) + intHouseHoldIncome
        count(5) = count(5) + 1
        Call povertystatus_5()
    Case cbxCountyState.Text = "Kenton,KY"
        income(6) = income(6) + intHouseHoldIncome
        count(6) = count(6) + 1
        Call povertystatus_6()
End Select

becomes this:

Dim index = cbxCountyState.SelectedIndex

income(index) = income(index) + intHouseHoldIncome
count(index) = count(index) + 1
PovertyStatus()

You really don't need a Select Case in PovertStatus either. You can just put your testIncome values into an array and index it too.