Getting Balance from selections made in program (Visual Basic)

[jmsutton334]

Hello, I am trying to get the balance from a program that I wrote, but seem to be having a little trouble with it. The formula for getting balance in this program is (balance = balance * (1 + interestRate). The current year is 2013, but the balance should be calculated for your selected year (e.g., 2015, 2016, 2017). I think repetition should be used, but not entirely sure of how to do that.

Public Class Form1

    Private Sub btnMediaEstimatedFund_Click(sender As Object, e As EventArgs) Handles btnMediaEstimatedFund.Click

        Dim interestRate, balance, initialBalanceSavings, initialBalanceCorporate, finalBalance As Double

        txtBoxEstimatedBudget.Enabled = False
        txtBoxAgenciesNeeded.Enabled = False

        If radButtonTraditional.Checked Then

            txtBoxAgenciesNeeded.Text = 3

        ElseIf radButtonEMedia.Checked Then

            txtBoxAgenciesNeeded.Text = 2

        End If

        If checkBoxSavings.Checked And radButton2015.Checked Then

            interestRate = 0.07

        ElseIf checkBoxCorporate.Checked Then

            interestRate = 0.05

        ElseIf checkBoxCorporate.Checked And checkBoxSavings.Checked Then

            interestRate = 0.12

        End If

        Dim inputtedData As String

        If checkBoxSavings.Checked Then
            Do

                inputtedData = InputBox("Please enter a balance for SAVINGS account between $500.00 and $3000.00", "Initial Savings Balance", "0.00")

                If inputtedData = "" Then

                    MsgBox("User chose to cancel calculation!")

                    Exit Sub

                Else

                    initialBalanceSavings = CType(inputtedData, Single)

                    If initialBalanceSavings > 3000 Or initialBalanceSavings < 500 Then MsgBox("Please enter a balance for SAVINGS account equal to or above $500.00 and no more than $3000.00", MsgBoxStyle.Critical, "Error")

                End If

            Loop Until initialBalanceSavings >= 500 And initialBalanceSavings <= 3000

        End If

        If checkBoxCorporate.Checked Then

            Do

                inputtedData = InputBox("Please enter a balance for CORPORATE account between $500.00 and $3000.00", "Initial Corporate Balance", "0.00")

                If inputtedData = "" Then

                    MsgBox("User chose to Cancel calculation!")

                    Exit Sub

                Else

                    initialBalanceCorporate = CType(inputtedData, Single)

                    If initialBalanceCorporate > 3000 Or initialBalanceCorporate < 500 Then MsgBox("Please enter a balance for CORPORATE account equal to or above $500.00 and no more than $3000.00", MsgBoxStyle.Critical, "Error")

                End If

            Loop Until initialBalanceCorporate >= 500 And initialBalanceCorporate <= 3000

        End If

        finalBalance = initialBalanceSavings + initialBalanceCorporate
        balance = finalBalance * (1 + interestRate)
        txtBoxEstimatedBudget.Text = balance

    End Sub

This is what I have so far, its getting me a balance (e.g. if I pick 7 % interest rate and put in 2000 as my initial balance it will give me 2140 as my estimated budget in the text box, but I also had the 2015 checkbox checked, so it is giving me the balance for 2013 I believe, not 2015).

Thanks for any help!!

[dunfiddlin]

I think repetition should be used

Why? There are formulas for the calculation of both simple and compound interest. Look 'em up. It's what Google's for. (There other search engines available apparently!)

[jmsutton334]

Would something like i= p * r * t work? (principal, rate, time)

[jmsutton334]

Could you give me a brief example of how to implement that into my code?

[dunfiddlin]

I reckon, if it's simple interest (it's not exactly clear from the initial formula you were given). The balance would simply be i + p.

[dunfiddlin]

Could you give me a brief example of how to implement that into my code?

Er ...

i = p * r * t
Balance = i + p

[jmsutton334]

And would t = the choice they make in year (e.g. 2015, 2016, 2017)?

[jmsutton334]

Public Class Form1

    Private Sub btnMediaEstimatedFund_Click(sender As Object, e As EventArgs) Handles btnMediaEstimatedFund.Click

        Dim interestRate, initialBalanceSavings, initialBalanceCorporate, finalBalance, time, i, balance As Double

        txtBoxEstimatedBudget.Enabled = False
        txtBoxAgenciesNeeded.Enabled = False

        If radButtonTraditional.Checked Then

            txtBoxAgenciesNeeded.Text = 3

        ElseIf radButtonEMedia.Checked Then

            txtBoxAgenciesNeeded.Text = 2

        End If

        If checkBoxSavings.Checked Then

            interestRate = 0.07

        ElseIf checkBoxCorporate.Checked Then

            interestRate = 0.05

        ElseIf checkBoxCorporate.Checked And checkBoxSavings.Checked Then

            interestRate = 0.12

        End If

        If radButton2015.Checked Then

            time = 2

        End If

        If radButton2016.Checked Then

            time = 3

        End If

        If radButton2017.Checked Then

            time = 4

        End If

        Dim inputtedData As String

        If checkBoxSavings.Checked Then
            Do

                inputtedData = InputBox("Please enter a balance for SAVINGS account between $500.00 and $3000.00", "Initial Savings Balance", "0.00")

                If inputtedData = "" Then

                    MsgBox("User chose to cancel calculation!")

                    Exit Sub

                Else

                    initialBalanceSavings = CType(inputtedData, Single)

                    If initialBalanceSavings > 3000 Or initialBalanceSavings < 500 Then MsgBox("Please enter a balance for SAVINGS account equal to or above $500.00 and no more than $3000.00", MsgBoxStyle.Critical, "Error")

                End If

            Loop Until initialBalanceSavings >= 500 And initialBalanceSavings <= 3000

        End If

        If checkBoxCorporate.Checked Then

            Do

                inputtedData = InputBox("Please enter a balance for CORPORATE account between $500.00 and $3000.00", "Initial Corporate Balance", "0.00")

                If inputtedData = "" Then

                    MsgBox("User chose to Cancel calculation!")

                    Exit Sub

                Else

                    initialBalanceCorporate = CType(inputtedData, Single)

                    If initialBalanceCorporate > 3000 Or initialBalanceCorporate < 500 Then MsgBox("Please enter a balance for CORPORATE account equal to or above $500.00 and no more than $3000.00", MsgBoxStyle.Critical, "Error")

                End If

            Loop Until initialBalanceCorporate >= 500 And initialBalanceCorporate <= 3000

        End If

This is what I got, I still feel like it isn't giving me the right number though... What do you think?

[jmsutton334]

I think it needs to be in a loop, but im not sure of how to write that...

[jmsutton334]

Public Class Form1

Private Sub btnMediaEstimatedFund_Click(sender As Object, e As EventArgs) Handles btnMediaEstimatedFund.Click

Dim interestRate, initialBalanceSavings, initialBalanceCorporate, finalBalance, time, i, balance As Double

txtBoxEstimatedBudget.Enabled = False
txtBoxAgenciesNeeded.Enabled = False

If radButtonTraditional.Checked Then

txtBoxAgenciesNeeded.Text = 3

ElseIf radButtonEMedia.Checked Then

txtBoxAgenciesNeeded.Text = 2

End If

If checkBoxSavings.Checked Then

interestRate = 0.07

ElseIf checkBoxCorporate.Checked Then

interestRate = 0.05

ElseIf checkBoxCorporate.Checked And checkBoxSavings.Checked Then

interestRate = 0.12

End If

If radButton2015.Checked Then

time = 2

End If

If radButton2016.Checked Then

time = 3

End If

If radButton2017.Checked Then

time = 4

End If

Dim inputtedData As String

If checkBoxSavings.Checked Then
Do

inputtedData = InputBox("Please enter a balance for SAVINGS account between $500.00 and $3000.00", "Initial Savings Balance", "0.00")

If inputtedData = "" Then

MsgBox("User chose to cancel calculation!")

Exit Sub

Else

initialBalanceSavings = CType(inputtedData, Single)

If initialBalanceSavings > 3000 Or initialBalanceSavings < 500 Then MsgBox("Please enter a balance for SAVINGS account equal to or above $500.00 and no more than $3000.00", MsgBoxStyle.Critical, "Error")

End If

Loop Until initialBalanceSavings >= 500 And initialBalanceSavings <= 3000

End If

If checkBoxCorporate.Checked Then

Do

inputtedData = InputBox("Please enter a balance for CORPORATE account between $500.00 and $3000.00", "Initial Corporate Balance", "0.00")

If inputtedData = "" Then

MsgBox("User chose to Cancel calculation!")

Exit Sub

Else

initialBalanceCorporate = CType(inputtedData, Single)

If initialBalanceCorporate > 3000 Or initialBalanceCorporate < 500 Then MsgBox("Please enter a balance for CORPORATE account equal to or above $500.00 and no more than $3000.00", MsgBoxStyle.Critical, "Error")

End If

Loop Until initialBalanceCorporate >= 500 And initialBalanceCorporate <= 3000

End If

finalBalance = initialBalanceSavings + initialBalanceCorporate
i = finalBalance * interestRate * time
balance = i + finalBalance
txtBoxEstimatedBudget.Text = balance

End Sub

Sorry this is the code I have now, not the one above

[Evil_Giraffe]

Couple of points. Firstly, use Decimal for any monetary value, not Double. Doubles cannot exactly represent decimal quantities and with repeated calculations will introduce a small error. You should reserve them for continuous values, and for all discrete values (such as money) use Decimal instead.

Secondly, you're probably looking at Compound Interest here. Calculate the interest for the year, round to pennies, and then add to the balance. Use that incremented balance as the input to the next year's interest calculation. I believe there is a formula for compound interest after n years, but since you need to round after each step, I'm not sure that'd work.

[Evil_Giraffe]

Here's an example of the error introduced when adding doubles: Adding 0.1 to itself 1000 times should result in 100, right?

Module Module1
 
    Sub Main()
        Dim decimalCounter As Decimal = 0
        Dim doubleCounter As Double = 0
 
        For additionCounter = 1 To 1000
            decimalCounter += 0.1D
            doubleCounter += 0.1
        Next
 
        Console.WriteLine("Decimal: {0}; Double: {1}", decimalCounter, doubleCounter)
        Console.ReadLine()
    End Sub
 
End Module

Result:

Decimal: 100.0; Double: 99.9999999999986

[jmsutton334]

This is my code I added a for loop but am still getting the wrong answer. I added a table of what the balances should be with the inputted numbers of (2000, Savings and 1000, Corporate)

Any help would be amazing!

I am getting $2805.10 for (Savings account 7%) for each year(2015-2017) that the user picks. I should be getting a different answer for each year....

Year Savings Account Corporate Account Saving + Corporate

2013 $2000.00 $1000.00 $3000.00
2014 $2140.00 $1050.00 $3190.00
2015 $2289.8 $1102.5 $3392.3
2016 $2450.086 $1157.625 $3607.711
2017 $2621.59202 $1215.50625 $3837.09827

Public Class Form1

Private Sub btnMediaEstimatedFund_Click(sender As Object, e As EventArgs) Handles btnMediaEstimatedFund.Click

Dim interestRate, initialBalanceSavings, initialBalanceCorporate, finalBalance, theYear, balance, subTotal As Double

txtBoxEstimatedBudget.Enabled = False
txtBoxAgenciesNeeded.Enabled = False

If radButtonTraditional.Checked Then

txtBoxAgenciesNeeded.Text = 3

ElseIf radButtonEMedia.Checked Then

txtBoxAgenciesNeeded.Text = 2

End If

If checkBoxSavings.Checked Then

interestRate = 0.07

ElseIf checkBoxCorporate.Checked Then

interestRate = 0.05

ElseIf checkBoxCorporate.Checked And checkBoxSavings.Checked Then

interestRate = 0.12

End If

If radButton2015.Checked Then

theYear = 2015

End If

If radButton2016.Checked Then

theYear = 2016

End If

If radButton2017.Checked Then

theYear = 2017

End If

Dim inputtedData As String

If checkBoxSavings.Checked Then
Do

inputtedData = InputBox("Please enter a balance for SAVINGS account between $500.00 and $3000.00", "Initial Savings Balance", "0.00")

If inputtedData = "" Then

MsgBox("User chose to cancel calculation!")

Exit Sub

Else

initialBalanceSavings = CType(inputtedData, Single)

If initialBalanceSavings > 3000 Or initialBalanceSavings < 500 Then MsgBox("Please enter a balance for SAVINGS account equal to or above $500.00 and no more than $3000.00", MsgBoxStyle.Critical, "Error")

End If

Loop Until initialBalanceSavings >= 500 And initialBalanceSavings <= 3000

End If

If checkBoxCorporate.Checked Then

Do

inputtedData = InputBox("Please enter a balance for CORPORATE account between $500.00 and $3000.00", "Initial Corporate Balance", "0.00")

If inputtedData = "" Then

MsgBox("User chose to Cancel calculation!")

Exit Sub

Else

initialBalanceCorporate = CType(inputtedData, Single)

If initialBalanceCorporate > 3000 Or initialBalanceCorporate < 500 Then MsgBox("Please enter a balance for CORPORATE account equal to or above $500.00 and no more than $3000.00", MsgBoxStyle.Critical, "Error")

End If

Loop Until initialBalanceCorporate >= 500 And initialBalanceCorporate <= 3000

End If

finalBalance = initialBalanceSavings + initialBalanceCorporate

For theYear = 2013 To 2017

subTotal = finalBalance * (1 + interestRate)
finalBalance = subTotal

Next

txtBoxEstimatedBudget.Text = FormatCurrency(finalBalance)

End Sub

[Evil_Giraffe]

I should be getting a different answer for each year....

If radButton2015.Checked Then
    theYear = 2015
End If

If radButton2016.Checked Then
    theYear = 2016
End If

If radButton2017.Checked Then
    theYear = 2017
End If

For theYear = 2013 To 2017
    subTotal = finalBalance * (1 + interestRate)
    finalBalance = subTotal
Next

When you look at those two bits of code next to each other, can you see the problem?

[Evil_Giraffe]

Also, you don't get fractions of a penny.

Year Savings Account Corporate Account Saving + Corporate 

2013 $2000.00 $1000.00 $3000.00
2014 $2140.00 $1050.00 $3190.00
2015 $2289.8 $1102.5 $3392.3
2016 $2450.086 $1157.625 $3607.711  <---- These figures would be rounded
2017 $2621.59202 $1215.50625 $3837.09827  <----- which will affect these calculations, which also would need to be rounded

[james40]

Do a search for: Time Value of Money. FV = PV*(1+i)^n where n = number of periods

Try this: http://en.wikipedia.org/wiki/Time_va..._a_present_sum

Hope this helps.