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Ferrixx
Ferrixx

Reputation: 3

Making a function that returns by reference in Visual Basic

So, hypothetically, if I were to be trying to write a sort-of "GetMax" function between two numbers, and I wanted to return the largest of the two by reference, so I could edit said returned reference variable directly from the calling of the function.

So in CPP it could look like this:

int& GetMax(int& a, int& b)
{
    if (a > b) {
        return a;
    }
    else {
        return b;
    }
}

And I could edit it like this:

int main(void)
{
    int a = 30;
    int b = 20;

    GetMax(a, b) = 10;

}

GetMax(a, b) = 10; Would change a's value.

Would I be able to do something similar in Visual Basic?

Function GetMax(ByRef a As Integer, ByRef b As Integer) As Integer

    If a > b Then
        Return a
    Else
        Return b
    End If

End Function

^ But instead of returning a value, it would return a reference, so I could treat the function the same way I did in the CPP example. I haven't really dedicated myself to learning visual basic, so I don't really know if I'm completely missing a key concept that would allow me to do the thing that I wish. Thank you ! :)

Upvotes: 0

Views: 260

Answers (2)

jmcilhinney
jmcilhinney

Reputation: 54417

The answer is no, so you'd have to do something like this to get the same result in the example you provided:

Sub SetMax(ByRef a As Integer, ByRef b As Integer, value As Integer)

    If a > b Then
        a = value
    Else
        b = value
    End If

End Sub

and call:

SetMax(a, b, 10)

Upvotes: 1

laancelot
laancelot

Reputation: 3207

The problem is that VB.NET doesn't want you to program cpp style. So while complex objects will always be references, primaries aren't. If you wanted to edit a primary in a sub you could put ByRef myVariable as Integer (or any other primary type) in your overload and it would work as a reference, but you won't be able to return it as a reference.

With complex objects, no problem. With primaries, forget that.

C# could do it, though, if it's the same to you.

Upvotes: 0

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