Question

I’m creating a simple calculator on VB6.

Here’s my code I’m working on:

    textScreen.Text = textScreen.Text & "+"

Here’s the result when I press some number buttons, followed by clicking on
the plus sign button several times:

    75+++++++

I would like the plus sign to appear only once, even if I click on
its button many times:

    92+

…and when I click on some number buttons again, followed by clicking
on the plus sign button, I would like the plus sign to show up again:

    58+4+

This is somehow similar to the default Calculator on Windows 7.

Answer 1

Well, there are different approaches for this. But in general, I wouldn’t just concatenate some string. This way you’ll have to parse the string later on, instead of just solving the requested term. Instead try to create some stack with your operations/numbers on it; just look on the web for calculator examples.

---

Anyway, for this, you’ll have to somehow store the last operation (e.g. did I input a digit or an operator?)

If you’d like to limit the calculator to simple operations without brackets etc. you can use a boolean value for this:

Dim lastOp As Boolean

Then, before adding the + (or any other operator):

If Not lastOp Then
    textScreen.Text = textScreen.Text & "+"
    lastOp = true
End If

When adding any digit (e.g.):

lastOp = false
textScreen.Text = textScreen.Text & "0"

(Don’t count on 100% error free code, I think I haven’t touched VB6 for like 8 years.)