[RESOLVED] Beginner requesting help!

[Ultrimo]

Hi, I'm new to visual basic and I've attempted to make a very simple calculator but I have no idea why it's not working. Of course I've done something stupid but I just can't find it.

The layout of the program is 3 text boxes:
FirstNumber
Operation
SecondNumber

1 Button:
Answer

1 Label:
Answer

The idea is to type in the first number, the operation (*/+-) and the second number, clicking the answer button. Then the label should hold the answer. This is my code:

Dim answerr, operation As String
Dim Firstnumber, Secondnumber As Double
Private Sub cmdAnswer_Click()
Firstnumber = Val(txtFirstnumber.Text)
Secondnumber = Val(txtSecondnumber.Text)
operation = txtOperation.Text
answerr = firstnumber operation secondnumber
Answerbox.Caption = answerr
End Sub


Thanks!

[MartinLiss]

First, while it's not your main problem, when you dim things this way

Dim Firstnumber, Secondnumber As Double

only Secondnumber is a Double - Firstnumber remains a Variant.

The main problem however is that while there are a limited number of things you can do if you want to use strings like "operation", but math operators is not one of them.

You can create a calculator using the MS scripting runtime and if you serach for "calculator" I'm sure you'll find examples.

[danecook21]

To do it your way you will need to check the operation string and have a condition for each possible operation you want to be able to perform.
Example:

Select Case operation
Case "+"
answer = firstnumber + secondnumber
Case "-"
answer = firstnumber - secondnumber
'etc
End Select

[Ultrimo]

First, while it's not your main problem, when you dim things this way

Dim Firstnumber, Secondnumber As Double

only Secondnumber is a Double - Firstnumber remains a Variant.

The main problem however is that while there are a limited number of things you can do if you want to use strings like "operation", but math operators is not one of them.

You can create a calculator using the MS scripting runtime and if you serach for "calculator" I'm sure you'll find examples.

I never knew that!

Thanks!
[QUOTE:danecook21]
To do it your way you will need to check the operation string and have a condition for each possible operation you want to be able to perform.
Example:

Select Case operation
Case "+"
answer = firstnumber + secondnumber
Case "-"
answer = firstnumber - secondnumber
'etc
End Select
[/QUOTE]

Yeah, in the end I just used radio buttons (I think they're called) and it worked a charm, thanks!