vb newbie part 2

[lolicon123]

i'm going to make a calculator. i have 4 txt boxes one for the first number a person should enter the second for if they want to use + - / etc.. third for the second number and fourth for the answer of the first and second number put together

code:
dim first as double
dim second as double
dim third as double
dim fourth as double

if secondbox.text = "+" then
firstbox.text + thirdbox.text = fourthbox.text
end if

i've done - / the same. but as you can probably see this aint working if anyone could tell me how to write this i would be thankfull

[lolicon123]

just for fun want to learn some vb basic

[ReidE96]

firstbox.text + thirdbox.text = fourthbox.text

should be

fourthbox.text = CInt(firstbox.text) + CInt(thirdbox.text)

[lolicon123]

yea i noticed that it looks like this now

txtFirst.Text = First
txtSecond.Text = Second
txtThird.Text = Third
txtFourth.Text = Fourth

Dim First As Double
Dim Second As Double
Dim Third As Double
Dim Fourth As Double

If Second = "+" Then
Fourth = First + Third
End If

still "getting argument not optional" thought


Edit: changed it too

First = CDbl(txtFirst.Text)
Third = CDbl(txtThird.Text)
Fourth = CStr(txtFourth.Text)


If Trim(txtSecond.Text) = "+" Then
txtFourth = txtFirst + txtThird
End If

but when i write 2 + 2 i get 22 as if the variables were not declared :O


edit2: funny thing is that if i use - or / instead of + it works :O hmm weird

[lolicon123]

also i would like it to be unable to be divided by zero i tried

"ElseIf txtFirst = "0" Or txtThird = "0" And txtSecond = "/" Then
MsgBox "unable to divide by zero""

not work here either i'm afraid :I

[ReidE96]

Ok, could you post your full source between [code] tags and I'll see if I can spot where you've gone wrong. Or someone else will spot it before I get to it. Either way works.

[lolicon123]

Private Sub Command1_Click()

First = CDbl(txtFirst.Text)
third = CDbl(txtThird.Text)
Fourth = CStr(txtFourth.Text)

If Trim(txtSecond.Text) = "+" Then
txtFourth = txtFirst + txtThird

ElseIf Trim(txtSecond.Text) = "*" Then
txtFourth = txtFirst * txtThird

ElseIf Trim(txtSecond.Text) = "-" Then
txtFourth = txtFirst - txtThird

ElseIf Trim(txtSecond.Text) = "/" Then
txtFourth = txtFirst / txtThird

ElseIf Trim(txtSecond.Text) = "+,*,-,/" Then
Else: MsgBox "Felaktigt räknesätt"

End If
End Sub



edit1:


looks like this now


Private Sub Command1_Click()

First = CDbl(txtFirst.Text)
third = CDbl(txtThird.Text)
Fourth = CStr(txtFourth.Text)

If Trim(txtSecond.Text) = "+" Then
txtFourth = Val(txtFirst) + Val(txtThird)

ElseIf Trim(txtSecond.Text) = "*" Then
txtFourth = txtFirst * txtThird

ElseIf Trim(txtSecond.Text) = "-" Then
txtFourth = txtFirst - txtThird

ElseIf Trim(txtSecond.Text) = "/" Then
txtFourth = txtFirst / txtThird

ElseIf Trim(txtSecond.Text) = "+,*,-,/" Then
Else: MsgBox "Felaktigt räknesätt"

End If

End Sub

and is working now about about divinding with zero can anyone help with that ?


as i said tried "ElseIf txtFirst = "0" Or txtThird = "0" And txtSecond = "/" Then
MsgBox "unable to divide by zero""

did not work :I

[ReidE96]

You should have used those First and Third variables you defined XD And you don't need fourth.

txtFourth.Text = First + Third

and so on. As to dividing by 0,

ElseIf Trim(txtSecond.Text) = "/" Then
txtFourth = txtFirst / txtThird

try changing to

ElseIf Trim(txtSecond.Text) = "/" Then
If Not Third = 0 Then txtFourth.Text = First / Third Else MsgBox "Divide by 0 error message here"

(change the message in red to something more appropriate )

[lolicon123]

You should have used those First and Third variables you defined XD And you don't need fourth.

lol but fourth is also defined how come i still need to write txtfourth = first + third ? why not just fourth = first + third that was what put me off to use that in the first place :O


is it just my VB messing with me or is their something wrong with your code on divide with zero? getting error else without if :S just like i did with mine :O

[ReidE96]

You've defined Fourth as a variable, which takes as its value the contents of txtFourth. First and Third are the same to txtFirst and txtThird. By doing txtFourth.Text = First + Third, you set the contents of txtFourth to the result of First + Third

And if that doesn't work, replace

If Not Third = 0 Then txtFourth.Text = First / Third Else MsgBox "Divide by 0 error message here"

with

If Not Third = 0 Then
    txtFourth.Text = First / Third
Else
    MsgBox "Divide by 0 error message here"
End If

[lolicon123]

You've defined Fourth as a variable, which takes as its value the contents of txtFourth. First and Third are the same to txtFirst and txtThird. By doing txtFourth.Text = First + Third, you set the contents of txtFourth to the result of First + Third
[/code]

oh so if i remove the defention and write Fourth = txtFourth.Text then Fourth = First + Third it will work? or can't the name of fourth be changed since it containts the result of first and third? do i have to rename the txtbox name for it too work with Fourth? :I

[lolicon123]

oh also the division by zero should it not be?:

If Not txtSecond.Text = "/" And Third Or First = 0 Then
txtFourth.Text = First / Third
Else
MsgBox "Divide by 0 error message here"
End If

in yours it looks like everytime you put a 0 in Third even if it's + * or - it will be error divided by zero still getting error else without if thought :Imy VB most really hate me


here is full code
Private Sub Command1_Click()

First = CDbl(txtFirst.Text)
Third = CDbl(txtThird.Text)

If Trim(txtSecond.Text) = "+" Then
txtFourth = First + Third

ElseIf Trim(txtSecond.Text) = "*" Then
txtFourth = First * Third

ElseIf Trim(txtSecond.Text) = "-" Then
txtFourth = First - Third

If Not txtSecond.Text = "/" And Third Or First = 0 Then
txtFourth.Text = First / Third
Else
MsgBox "Divide by 0 error message here"

ElseIf Trim(txtSecond.Text) = "+,*,-,/" Then
Else: MsgBox "Felaktigt räknesätt"

End If

End Sub

[ReidE96]

The bit I added is to go inside the condition you already have for dividing

ElseIf Trim(txtSecond.Text) = "-" Then
txtFourth = First - Third
 
If Not txtSecond.Text = "/" And Third Or First = 0 Then
txtFourth.Text = First / Third
Else
MsgBox "Divide by 0 error message here"
End If
 
ElseIf Trim(txtSecond.Text) = "+,*,-,/" Then

Highlight in red Also, you have to do txtFourth.Text = First + Third (and so on) or it won't know what to do.

[lolicon123]

hm well that triggers my other msgbox when using /.

ElseIf Not (txtSecond.Text) = "/,*,-,+" Then
MsgBox "felaktigt räknesätt"
full:



First = CDbl(txtFirst.Text)
Third = CDbl(txtThird.Text)


If Trim(txtSecond.Text) = "+" Then
txtFourth.Text = Val(txtFirst) + Val(txtThird)

ElseIf Trim(txtSecond.Text) = "*" Then
txtFourth.Text = txtFirst * txtThird

ElseIf Trim(txtSecond.Text) = "-" Then
txtFourth.Text = txtFirst - txtThird

If Not txtSecond.Text = "/" And Third Or First = 0 Then
txtFourth.Text = First / Third
Else
MsgBox "Divide by 0 error message here"
End If

ElseIf Not (txtSecond.Text) = "/,*,-,+" Then
MsgBox "felaktigt räknesätt"

End If


i suppose you mean for it to be like this?

man i don't get how it can trigger the second msgbox when using / it's like it's ignoring just that / of that part of the code :S gaaah

[ReidE96]

No, I mean:

First = CDbl(txtFirst.Text)
Third = CDbl(txtThird.Text)
 
If Trim(txtSecond.Text) = "+" Then
    txtFourth.Text = First + Third
 
ElseIf Trim(txtSecond.Text) = "*" Then
    txtFourth.Text = First * Third
 
ElseIf Trim(txtSecond.Text) = "-" Then
    txtFourth.Text = First - Third
 
ElseIf Trim(txtSecond.Text) = "/" Then
    If Not Third = 0 Then
        txtFourth.Text = First / Third
    Else
        MsgBox "Divide by 0 error message here"
    End If

ElseIf Not (txtSecond.Text) = "/,*,-,+" Then
     MsgBox "felaktigt räknesätt"
 
End If