I have a problem with adding more than one number in calculator..the problem is while adding 1+2 answer is 3 and when i do 1+2+3 the answer is 5 and not 6 why so.. ihave tried different method of creating array for storing the value but nothing seems to work and i am getting a error while i type Value1 <> " THen. i get the error as conversion of string to type double is not valid.whereas i have already declared the Value1 As Double...please help

For the error in conversion, that's means maybe the imputed data are taken as string or the problem is that you do not take care of the operations (signs {+,-,/,*}).

Coming to your actual problem of not getting the desired answer, this can be coursed by you not taking care of the signs, if I were you I would declare a variable that will hold the operations so that they won't interfere with your calculations. If you had done that you would also declare variables to hold the values.

On mine I made mine to be able to hold 2 values and one operation, meaning the calculation is like this (1) (+) (1) right, on the left I have the first value and at the center I have the operation then on the right I have the value again so I would have 3 variables to hold value one, value 2, and then the operation and you would simply check which operation was used then process like this:

 If Operation = "+" Then
 Answer = Value1 + Value2
 Else
 If Operation = "-" Then
 Answer = Value1 + Value2
 End If
 End If

Now coming to your problem you simple need to add another variables which will hold the third value and the second operation then proceed with your calculations.

@Mr M
In line5 you probably mean: Answer = Value1 - Value2 ?
@Arun
1) I would use the read out (textbox ?) also as a variable to keep on with the operations.
2) I would use select case stements for your operations code

Lacking code, I would hazard a guess that it is not doing a running calculation (1+2+3) but only displaying the result of the last operation (2+3).

Hi thanks for replying actually i tried all methods which u gave but it does works.i am posting some parts of my code and here it is
Private Sub ButAdd_Click(sender As Object, e As EventArgs) Handles ButAdd.Click

        If Value1 <> "" Then
         Private Sub ButAdd_Click(sender As Object, e As EventArgs) Handles ButAdd.Click
        If Value1 <> "" Then
            Runningtotal = Runningtotal + Value1
        End If
        Add = True
        Value1 = Val(TextBox1.Text)
    End Sub

    Private Sub ButEqu_Click(sender As Object, e As EventArgs) Handles ButEqu.Click
        Value2 = Val(TextBox1.Text)
        If Add = True Then
            If Runningtotal = "" Then
                Answer = Value1 + Value2
            Else
                Answer = Runningtotal + Value2
                TextBox1.Text = Answer
            End If
        End If
    End Sub


        Runningtotal = Runningtotal + Value1
    End If
    Add = True
    Value1 = Val(TextBox1.Text)
End Sub

Private Sub ButEqu_Click(sender As Object, e As EventArgs) Handles ButEqu.Click
    Value2 = Val(TextBox1.Text)
    If Add = True Then
        If Runningtotal = "" Then
            Answer = Value1 + Value2
        Else
            Answer = Runningtotal + Value2
            TextBox1.Text = Answer
        End If
    End If
End Sub
here running Runningtotal is another variable which i have declared as a variable for storing the answer of prev calculation 

@Minimalist, yes thanks didn't notice that error while typing.

@Arun_14, I believe you can minimize the number of buttons by either placing your similar or relative codes on one button and separate by "IF" statement or even place them on a function.

Also instead of:

 If Add = True Then

You need to do it like this:

 If Operation = ("your operation here") Then
 ' That was your first operation so do your first calculations here
 RunningAnswer = Value1 (your operation here) Value2
If RunningAnswer IsNot Nothing And SecOperation = ("your second operation here") Then
 Answer = RunningAnswer (your second operation here) SecValue2
 ' Then you can go on adding the else and repeat the above if statement
 ' To ensure you recognize all the operations.
 End If
 End If

This is because the use may not always want to use both same operations, this will help if there are also a mixture of operation such as: 5*2-5 or 20/2+8, etc.

Here I just post here a simple example of calculation

Public Class Form1
    Dim runningtotal As Double = 0.0#
    Dim add As Boolean = False


    Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click
        If add Then
            runningtotal += Val(TextBox1.Text)

        Else
            If Not String.IsNullOrWhiteSpace(TextBox1.Text) Then
                runningtotal = Val(TextBox1.Text)
            End If

        End If
        add = True
        Me.Text = runningtotal
        TextBox1.Text = ""
        TextBox1.Focus()

    End Sub


    Private Sub Button2_Click(sender As System.Object, e As System.EventArgs) Handles Button2.Click
        runningtotal += Val(TextBox1.Text)
        add = False
        Me.Text = runningtotal
        TextBox1.Text = ""
        TextBox1.Focus()
    End Sub


End Class

Hope it can give you a way to solve your problem.

Edited 1 Year Ago by Shark_1

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