Another n00b question(vb4)

[Andybebad]

I'm trying to make an interest calculator, but when i press the compute button, the total investment box only shows $0.00. What am I doing wrong?

Compute button code

Private Sub cmdComm_Click()
'Use for loop to calculate a final total
'investment using compound interest.
'
'intNum is a loop control variable
'sngIRate is the annual interest rate
'intTerm is the Number of years in the investment
'curInitInv is the investors initial investment
'sngInterest is the total interest paid
    Dim sngIRate As Single, sngInterest As Single
    Dim intTerm As Integer, intNum As Integer
    Dim curInitInv As Currency
    
    'Error-checking
    If ErrorCheck() = 1 Then
        Exit Sub
    End If
    
    sngIRate = txtIR.Text / 100
    intTerm = txtTerm.Text
    
    curInitInv = txtIA.Text
    sng = 1     'Begin at first compound
    
    'Use loop to calculate total compound amount
    For intNum = 1 To intTerm
        sngInterest = sngInterest * (1 + sngIRate)
    Next intNum
    
    'Now we have total interest,
    'calculate the total investment
    'at the end of N years
    txtTotal.Text = Format(curInitInv * sngInterest, "$###,##0.00")
    
End Sub

[DrDave1958]

You're trying to compute (mix) numbers and text, which you can't do. Look at the following example and insert this same format throughout your code.


sngIRate = val(txtIR.Text) / 100

If you still have problems, post back.

-Dave-

[Andybebad]

It's still doing it...

Private Sub cmdComm_Click()
    Dim sngIRate As Single, sngInterest As Single
    Dim intTerm As Integer, intNum As Integer
    Dim curInitInv As Currency
    
    If ErrorCheck() = 1 Then
        Exit Sub
    End If
    
    sngIRate = Val(txtIR.Text) / 100
    intTerm = Val(txtTerm.Text)
    
    curInitInv = Val(txtIA.Text)
    sng = 1     'Begin at first compound
    
    'Use loop to calculate total compound amount
    For intNum = 1 To Val(intTerm)
        sngInterest = Val(sngInterest) * Val(1 + Val(sngIRate))
    Next intNum
    
    'Now we have total interest,
    'calculate the total investment
    'at the end of N years
    txtTotal.Text = Format(Val(curInitInv) * Val(sngInterest), "$###,##0.00")
        Exit Sub
    
End Sub

[DrDave1958]

I'm not exactly sure how this line is interpreted...
sngInterest = Val(sngInterest) * Val(1 + Val(sngIRate)), specifically the "Val(1 + Val(sngIRate))" part.

The best practice is to use variables dimensioned as some number type rather than using the "Val(text.text)" format.

That said, try this,
sngInterest = Val(sngInterest) * (1 + Val(sngIRate)).

Have you tried to "step" thru the code, watching the value of the variables at each line?


-Dave-

[Andybebad]

I got it to work with this:

Private Sub cmdComm_Click()
    Dim sngIRate As Single, sngInterest As Single
    Dim intTerm As Integer, intNum As Integer
    Dim curInitInv As Currency
    
    If ErrorCheck() = 1 Then
        Exit Sub
    End If
    sngInterest = Val(txtIA.Text)
    intTerm = Val(txtTerm.Text)
    sngIRate = Val(txtIR.Text)
    curInitInv = Format(Val(sngInterest) * (sngIRate))
    txtTotal.Text = Format(Val(curInitInv) * (intTerm), "$###,##0.00")
    
    End Sub

[Andybebad]

Thanks for your help!