I am trying to implement a simple calculation to output Total Price using Visual Basic.NET
I want to read Original Price and Shipping Weight then use it in the calculation. The problem is,
When I enter any values, both variables will return only first digit
For example, if enter 23 it will return 2
Dim originalPrice As Double
Dim commissionPrice As Double
Dim shippingWeight As Double
Dim totalPrice As Double
Console.Write("Enter Original Price: ")
originalPrice = Double.Parse(Console.ReadLine(originalPrice))
Console.Write("Enter Shipping Weight: ")
shippingWeight = Double.Parse(Console.ReadLine(shippingWeight))
shippingWeight = shippingWeight * 7
If (originalPrice + shippingWeight >= 200) Then
commissionPrice = (originalPrice + shippingWeight) * 0.03
Else
commissionPrice = 5
End If
totalPrice = commissionPrice + originalPrice + shippingWeight
Console.WriteLine(originalPrice)
Console.WriteLine(commissionPrice)
Console.WriteLine(shippingWeight)
Console.WriteLine(totalPrice)
I think that your problem is that you are passing the variable to the Console.read()
In this way should work.
Dim originalPrice As Double
Dim commissionPrice As Double
Dim shippingWeight As Double
Dim totalPrice As Double
Console.Write("Enter Original Price: ")
originalPrice = Double.Parse(Console.ReadLine())
Console.Write("Enter Shipping Weight: ")
shippingWeight = Double.Parse(Console.ReadLine())
shippingWeight = shippingWeight * 7
If (originalPrice + shippingWeight >= 200) Then
commissionPrice = (originalPrice + shippingWeight) * 0.03
Else
commissionPrice = 5
End If
totalPrice = commissionPrice + originalPrice + shippingWeight
Console.WriteLine(originalPrice)
Console.WriteLine(commissionPrice)
Console.WriteLine(shippingWeight)
Console.WriteLine(totalPrice)
Console.Read()
Related
Following VB.Net code does not return the expected result:
Dim sum As Single = 535353
Dim vat As Single = Math.Round(sum * 0.19, 2)
Dim total As Single = Math.Round(sum + vat, 2)
Debug.WriteLine(String.Format("sum: {0:c2}, vat: {1:c2}, total: {2:c2}", sum, vat, total))
vat is correctly set to 101717.07, but the result of "total" is 636070.063.
Why does the last Math.round function returns 3 digits, and the wrong result?
Try it using Double
Dim sum As Double = 535353
Dim vat As Double = Math.Round(sum * 0.19, 2)
Dim total As Double = Math.Round(sum + vat, 2)
' sum 535353.0 Double
' total 637070.07 Double
' vat 101717.07 Double
I'm trying to solve the following system of equations in VBA:
I have looked for other similar questions and I can't find any with suitable solutions. I have already solved the equations in a worksheet by simply entering the equations as formulae is separate cells (which will initially create a circular reference warning) and the enabling iterative calculation) - given that I know DR will always be greater than PR, I thought an iterative approach of incrementally reducing PR from an initial value of DR would work in VBA. For reference, the worksheet used is shown below:
The formula in G9 is =(G8*B6)/(G10+273.15), i.e. equation 2 (see above), and the formula in G10 is =(B6+(B6*(-1+((G9*(B3-B35))/(B3-B35))^0.263)/B34))-B33*(B6+(B6*(-1+((G9*(B3-B35))/(B3-B35))^0.263)/B34)), i.e. equation 1 (see above).
When I try to do this programmatically in VBA by reducing PR incrementally from an initial value of DR, it doesn't work. My code is below:
Sub ChargeTempAndPressureCalculations()
Dim AP_hPa As Double
Dim AP_psi As Double
Dim TIn_C As Double
Dim TIn_K As Double
Dim PR As Double
Dim Ei As Double
Dim Et As Double
Dim Vci As Double
Dim DR As Double
Dim TOut_C As Double
AP_hPa = 1029 'Input
AP_psi = AP_hPa * 100 * 0.000145038
TIn_C = 15 'Input
TIn_K = TIn_C + 273.15
Et = 0.75 'Input
Ei = 0.75 'Input
Vci = 0.5 'Input
DR = 2.7103502887329 'Input
PR = DR
Do Until TOut_C = (TIn_K + (TIn_K * (-1 + ((PR * (AP_psi - Vci)) / (AP_psi - Vci)) ^ 0.263) / Et)) - Ei * (TIn_K + (TIn_K * (-1 + ((PR * (AP_psi - Vci)) / (AP_psi - Vci)) ^ 0.263) / Et)) And PR = (DR * TIn_K) / (TOut_C + 273)
PR = PR - 0.00000000001
Loop
Debug.Print "Charge air temperature = " & TOut_C
Debug.Print "Pressure Ratio = " & PR
End Sub
It's clearly the loop that's the issue but what is it that I'm doing wrong?
Edit:
I've split equation 1 to prevent the 'Equation too complex' error observed by another user, mentioned in the comments. I've also added a control to prevent the number of steps going above 1000.
Sub ChargeTempAndPressureCalculations()
Dim AP_hPa As Double
Dim AP_psi As Double
Dim TIn_C As Double
Dim TIn_K As Double
Dim PR As Double
Dim Ei As Double
Dim Et As Double
Dim Vci As Double
Dim DR As Double
Dim TOut_C As Double
Dim A As Double
Dim B As Double
Dim i As Integer
AP_hPa = 1029 'Input
AP_psi = AP_hPa * 100 * 0.000145038
TIn_C = 15 'Input
TIn_K = TIn_C + 273.15
Et = 0.75 'Input
Ei = 0.75 'Input
Vci = 0.5 'Input
DR = 2.7103502887329 'Input
PR = DR
Do Until i > 1000 Or (TOut_C = A - Ei * B And PR = (DR * TIn_K) / (TOut_C + 273))
'Spliting equation for TOut_C to simplify the expression and prevent an error
A = (TIn_K + (TIn_K * (-1 + ((PR * (AP_psi - Vci)) / (AP_psi - Vci)) ^ 0.263) / Et))
B = (TIn_K + (TIn_K * (-1 + ((PR * (AP_psi - Vci)) / (AP_psi - Vci)) ^ 0.263) / Et))
PR = PR - 0.00000000001
i = i + 1
Loop
Debug.Print "Charge air temperature = " & TOut_C
Debug.Print "Pressure Ratio = " & PR
End Sub
Having read the answer provided, I'm still none the wiser as to how to resolve my issue.
I've gone over your calculation a bit more and I presume you want to stop if the increment of PR and TOut_C is very marginal...
The below code does exactly that. It calculates TOut_C at a given PR, it subsequently calculates the PR corresponding to that TOut_C, the loop then substitutes the newly calculated PR into the TOut_C calculation and so on.
It calculates the difference between the substitute calculation and the previous calculation and if there is no longer a 'large' offset between the two it stops the loop.
Sub ChargeTempAndPressureCalculations()
Dim AP_hPa As Double
Dim AP_psi As Double
Dim TIn_C As Double
Dim TIn_K As Double
Dim PR As Double
Dim Ei As Double
Dim Et As Double
Dim Vci As Double
Dim DR As Double
Dim TOut_C As Double
AP_hPa = 1029 'Input
AP_psi = AP_hPa * 100 * 0.000145038
TIn_C = 15 'Input
TIn_K = TIn_C + 273.15
Et = 0.75 'Input
Ei = 0.75 'Input
Vci = 0.5 'Input
DR = 2.7103502887329 'Input
PR = DR
dTOut_C = 1 'Set to arbitrary number to initialize the loop
dPR = 1 'Set to arbitrary number to initialize the loop
Do Until dPR < 0.0000000001 And dTOut_C < 0.0000000001
'Calculate the TOut_C and PR
TOut_C = (TIn_K + (TIn_K * (-1 + ((PR * (AP_psi - Vci)) / (AP_psi - Vci)) ^ 0.263) / Et)) - Ei * (TIn_K + (TIn_K * (-1 + ((PR * (AP_psi - Vci)) / (AP_psi - Vci)) ^ 0.263) / Et))
PR = (DR * TIn_K) / (TOut_C + 273)
'Calculate difference relative to last calculation
dPR = PR - PR0
dTOut_C = TOut_C - TOut_C0
'Set the last calculation as previous calculation and re-do loop
PR0 = PR
TOut_C0 = TOut_C
Loop
Debug.Print "Charge air temperature = " & TOut_C
Debug.Print "Pressure Ratio = " & PR
End Sub
Given your initial input the output is:
Charge air temperature = 93.2076926574912
Pressure Ratio = 2.13263525413933
Was that what you were looking for ?
PS: Technically what you should do is mathematically rewrite the equation to solve for PR based on DR as that is in essence what you are doing...
Note that in:
Do Until TOut_C = ...
the = sign is a comparisson and not an assignment. As TOut_C has not been used yet, it is set to zero by VB and so you are comparing whether the right hand side is zero. This does not seem to be your intention, as you use TOut_C in the AND part as TOut_C + 273 which then would always be 273.
But if you want to compare with zero, then note that the RHS will probably never become zero in floating point arithmetic and you must compare with an "epsilon", a small value that is your precission threshold. For example:
Private Const eps = 0.00000000001 ' must be smaller than your step size
Do Until Abs(TOut_C - RHS) < eps
I leave fixing this to you. (I also get an error "Expression too complex" on my Excel version.)
There is primarily two problems...
In your Do..Loop you want the code to break on TOut_C = <something based on PR> AND PR = <something based on TOut_C>
Both equation however lead to a double datatype, this is almost imposibble to have that be an = comparison as the likelyhood of hitting that equal point are virtualy zero (as I explained here)
So, you would want to set a more flexible parameter such as TOut_C > 63 for example.
The second thing that I can find is that the equations are just that, equations. So they'll produce a number but as that number is the result of the equation, but what would define the endpoint ? TOut_C is never defined and subsequently compared as indicated, your code starts with PR being 2.71... but Tout_C is 0.
So could you elaborate more on the correlation between TOut_C and PR and what would be the solution values for either or both of them ? Or are you trying to solve a balance point i.e. for a which TOut_C do both functions achieve the same result ? (That would require mathematically re-writing either function to express the same output) So rewrite the function for PR to produce Tout_C...
The loop works (i.e. it loops) if you write it like so...
It doesn't solve it, but at least you know it loops...
Do Until TOut_C = 15 And PR = 22
TOut_C = (TIn_K + (TIn_K * (-1 + ((PR * (AP_psi - Vci)) / (AP_psi - Vci)) ^ 0.263) / Et)) - Ei * (TIn_K + (TIn_K * (-1 + ((PR * (AP_psi - Vci)) / (AP_psi - Vci)) ^ 0.263) / Et))
PR = (DR * TIn_K) / (TOut_C + 273)
PR = PR - 0.00000000001
Loop
See http://www.decisionmodels.com/calcsecretsc.htm on how Excel processes circular references. Basically, it just calculates each cell, ignoring the circular reference and then it updates the values in each iteration.
Applying this to your VBA routine produces the following sub routine:
Sub ChargeTempAndPressureCalculations()
' input variables
Dim AP_hPa As Double
Dim AP_psi As Double
Dim TIn_C As Double
Dim TIn_K As Double
Dim Ei As Double
Dim Et As Double
Dim Vci As Double
Dim DR As Double
' temporary variables
Dim Td As Double
Dim Pd As Double
Dim A As Double
' output variables
Dim TOut_C As Double
Dim PR As Double
' iteration control
Dim eps As Double
Dim i As Integer
AP_hPa = 1029
AP_psi = AP_hPa * 100 * 0.000145038
TIn_C = 15
TIn_K = TIn_C + 273.15
Et = 0.75
Ei = 0.75
Vci = 0.5
DR = 2.7103502887329
PR = DR
eps = 0.00000000001
i = 0
Do
Td = TOut_C ' remember values from previous iteration ( 'd' means 'delta')
Pd = PR
A = (TIn_K + (TIn_K * (-1 + ((PR * (AP_psi - Vci)) / (AP_psi - Vci)) ^ 0.263) / Et))
TOut_C = A - Ei * A
PR = (DR * TIn_K) / (TOut_C + 273)
i = i + 1
Debug.Print TOut_C & ", " & PR & "(" & Abs(Td - TOut_C) & ", " & Abs(Pd - PR) & ")" ' show progression
' loop until the difference is less than eps or max iterations reached
Loop While (i < 100 And (Abs(Td - TOut_C) > eps And Abs(Pd - PR) > eps))
Debug.Print "Charge air temperature = " & TOut_C
Debug.Print "Pressure Ratio = " & PR
Debug.Print "number of iterations: " & i
End Sub
Output:
100.835921416446, 2.08911822261291(100.835921416446, 0.621232066119993)
92.5738330344343, 2.13633297880164(8.26208838201211, 4.72147561887288E-02)
93.2611120407512, 2.13232420812257(0.687279006316899, 4.00877067907057E-03)
93.2031960023579, 2.13266144103602(5.79160383933299E-02, 3.37232913455665E-04)
93.2080712078647, 2.13263304962791(4.87520550686327E-03, 2.83914081067316E-05)
93.2076607895546, 2.13263543972443(4.10418310181626E-04, 2.39009651137323E-06)
93.2076953402811, 2.13263523851592(3.45507265677725E-05, 2.01208508077144E-07)
93.2076924316548, 2.1326352554545(2.90862628560262E-06, 1.6938581648418E-08)
93.2076926765153, 2.13263525402854(2.44860444809092E-07, 1.42596112695514E-09)
93.2076926559019, 2.13263525414858(2.06133563551703E-08, 1.200430865822E-10)
93.2076926576372, 2.13263525413848(1.73530168012803E-09, 1.01052499701382E-11)
93.2076926574912, 2.13263525413933(1.46073375617561E-10, 8.5043083686287E-13)
Charge air temperature = 93.2076926574912
Pressure Ratio = 2.13263525413933
number of iterations: 12
I am having issues trying to make a calculator that accurately calculates deposits plus the amount of interest that is added monthly. I dont know how to incorporate a loop that can add monthly deposits to total deposits, then adds the total deposits plus total interest times the interest rate / 100 / 12 to the total deposits. Here is what I have so far. Sorry am super new to VB !
Dim intMonthlyDeposit As Interger
Dim intMonthsTotal As Integer
Dim intAnnualRate As Interget
Dim decTotalDeposits As Decimal
Dim decTotalInterest As Decimal
Dim decTotalTotal As Decimal
Try
intMonthlyDeposit = CInt(txtMonthlyDeposits.Text)
intMonthsTotal = CInt(txtMonths.Text)
decAnnualRate = CDec(txtAnnualRate.Text)
decTotalDeposits = 0
decTotalInterest = 0
decTotalTotal = 0
decTotalDeposits = decMonthlyDeposit * intMonthsTotal
decTotalInterest = decTotalDeposits * (decAnnualRate / 100)
decTotalTotal = decTotalDeposits + decTotalInterest
lblTotDeposit.Text = decTotalDeposits.ToString("C")
lblTot.Text = decTotalTotal.ToString("C")
lblTotInterest.Text = decTotalInterest.ToString("C")
Catch ex As Exception
MsgBox("Enter a Valid Number")
End Try
End Sub
This is how I implemented the loop for calculating total interest and total deposits correctly.
For index As Integer = 1 To intMonthsTotal Step 1
decTotalDeposits += decMonthlyDeposit
decTotalInterest += (decTotalDeposits + decTotalInterest) * ((decAnnualRate / 100) / 12)
I don't deal with VB. I am helping my mother with her homework and just cant think straight anymore on what to do with this statement.
Private Sub btnTotal_Click(sender As Object, e As EventArgs) Handles btnTotal.Click
Dim intPackA As Integer = 0
Dim intPackB As Integer = 0
Dim intPackC As Integer = 0
Dim SavingsPriceB As Decimal = 0.0
Dim SavingsPriceC As Decimal = 0.0
Dim TotalPrice As Decimal = 0.0
lblTotal.Text = String.Empty
If radPackA.Checked Then
TotalPrice = 9.95
lblTotal.Text = TotalPrice
If Integer.TryParse(txtHours.Text, intPackA) Then
If intPackA > 10 Then
TotalPrice = TotalPrice + ((intPackA - 10) * 2)
lblTotal.Text = TotalPrice
End If
End If
If chkSavings.Checked Then
SavingsPriceB = 14.95 + ((intPackB - 20) * 1)
SavingsPriceC = 19.95
If TotalPrice < SavingsPriceB And TotalPrice < SavingsPriceC Then
lblTotal.Text = TotalPrice & ", no savings with Package B or C"
End If
End If
ElseIf radPackB.Checked Then
TotalPrice = 14.95
lblTotal.Text = TotalPrice
If Integer.TryParse(txtHours.Text, intPackB) Then
If intPackB > 20 Then
TotalPrice = TotalPrice + ((intPackB - 20) * 1)
lblTotal.Text = TotalPrice
End If
End If
If chkSavings.Checked Then
End If
ElseIf radPackC.Checked Then
TotalPrice = 19.95
lblTotal.Text = TotalPrice
End If
If chkNonprofit.Checked Then
TotalPrice = Format((TotalPrice - ((TotalPrice / 100) * 20)), ".00")
lblTotal.Text = TotalPrice & ControlChars.CrLf & "Non-Profit Organization discount applied"
End If
End Sub
It's the If chkSavings.Checked that's giving me problem.
This is the program as designed. There is a label bellow the packages that displays the total.
When the Potential Savings is checked, it should also display the amount you could save if you use a different package.
So if I put Package A, 5 hours, 20% discount it should say $7.96, no savings with Package B or C. For Package A, 25 hours it should say $39.95, save $20.00 with Package B, and save $20.00 with Package C
The code I have does not print it even the first part.
Package A and less then 10 hours = $9.95, every additional hour is $2.00 more
Package B and less then 20 hours = $14.95, every additional hour is $1.00 more
Package C with unlimited hours is = $19.95
So My question is, what am I doing wrong in my code or how could I achieve what I am looking for.
I've got this program to calculate the cost of sheets of paper. First the prices and bundles are declared and intialized. Then I use if else statements with division and modulos to break down the bundle into charging rates. Although my paper bundle amounts are correctly computed, my total costs are off. Can anyone spot what I'm doing wrong here?
Module Paper
Sub Main()
'declare variables
Dim PaperAmountReq As Double
Dim PricePer_1_Sheet As Double = 0.1
Dim PricePer_100_Sheets As Double = 0.055
Dim PricePer_500_Sheets As Double = 0.04
Dim PricePer_1000_Sheets As Double = 0.03
Dim NumberOfSingles As Double = 0
Dim NumberOf100s As Double = 0
Dim NumberOf500s As Double = 0
Dim Numberof1000s As Double = 0
Dim TotalCost As Double
Console.Write("Enter number of sheets of paper needed: ")
PaperAmountReq = Console.Readline
If PaperAmountReq / 1000 >= 1 Then
Numberof1000s = PaperAmountReq \ 1000
PaperAmountReq = PaperAmountReq Mod 1000
End If
If PaperAmountReq / 500 >= 1 Then
NumberOf500s = PaperAmountReq \ 500
PaperAmountReq = PaperAmountReq Mod 500
End If
If PaperAmountReq / 100 >= 1 Then
Numberof100s = PaperAmountReq \ 100
PaperAmountReq = PaperAmountReq Mod 100
End If
If PaperAmountReq / 1 = PaperAmountReq Then
NumberOfSingles = PaperAmountReq
End If
'TotalCost = (Convert.ToDouble(Numberof1000s) * PricePer_1000_Sheets) + (Convert.ToDouble(NumberOf500s) * PricePer_500_Sheets) + (Convert.ToDouble(Numberof100s) * PricePer_100_Sheets) + (Convert.ToDouble(NumberOfSingles) * PricePer_1_Sheet)
TotalCost = (Numberof1000s * PricePer_1000_Sheets) + (NumberOf500s * PricePer_500_Sheets) + (Numberof100s * PricePer_100_Sheets) + (NumberOfSingles * PricePer_1_Sheet)
Console.WriteLine("Number of 1000 packages: " & Numberof1000s)
Console.WriteLine("Number of 500 packages: " & Numberof500s)
Console.WriteLine("Number of 100 packages: " & Numberof100s)
Console.WriteLine("Number of singles packages: " & NumberOfSingles)
Console.Write("Total Cost: " & TotalCost)
End Sub
End Module
With this:
If PaperAmountReq / 1000 >= 1 Then
Numberof1000s = PaperAmountReq \ 1000
PaperAmountReq = PaperAmountReq Mod 1000
End If
if you have 1500, you are setting Numberof1000s equal to 1 - not 1000. So when you calculate your total cost, your value of (presumably) cost/sheet is being multiplied by 1 instead of 1000.
Either change your equation here
TotalCost = (Numberof1000s * PricePer_1000_Sheets) + (NumberOf500s * PricePer_500_Sheets) + (Numberof100s * PricePer_100_Sheets) + (NumberOfSingles * PricePer_1_Sheet)
to be something like
TotalCost = (Numberof1000s * PricePer_1000_Sheets * 1000) + (NumberOf500s * PricePer_500_Sheets * 500) + (Numberof100s * PricePer_100_Sheets * 100) + (NumberOfSingles * PricePer_1_Sheet * 1)
or adjust the PricePer_XXX_Sheets values to be the equivalent values.
Dim PricePer_1_Sheet As Double = 0.1
Dim PricePer_100_Sheets As Double = 0.055 * 100
Dim PricePer_500_Sheets As Double = 0.04 * 500
Dim PricePer_1000_Sheets As Double = 0.03 * 1000
Well your numberof variables should be integers or maybe bigintegers if not big enough as should PaperAmountReq
Your code seems to be assuming integer division
in these segments
If PaperAmountReq / 500 >= 1 Then
NumberOf500s = PaperAmountReq \ 500
PaperAmountReq = PaperAmountReq Mod 500
End if
in actual fact because you are using doubles, it's doing floating point division.
I'd also recommend that you use decimal instead of double for your price? and Total Cost variables.
Doubles are very precise, but often very inaccurate.
Looks like you need to convert the NumberOfXXXs variables to sheets, rather than bundles.
Your formula at the end uses per-sheet costs with per-bundle numbers. Either update the costs to be per-bundle, or update the bundle numbers to equal the round number of sheets in that bundle:
TotalCost = NumberOf1000s * 1000 * PricePer_1000_Sheets
Dim PricePer_100_Sheets As Double = 0.055
Dim PricePer_500_Sheets As Double = 0.04
Dim PricePer_1000_Sheets As Double = 0.03
should be
Dim PricePer_100_Sheets As Double = 0.055 * 100
Dim PricePer_500_Sheets As Double = 0.04 * 500
Dim PricePer_1000_Sheets As Double = 0.03 * 1000