[RESOLVED] Function as Parameter

[hannibal smith]

Hello, I'm trying to use this method that I found online:

Function Bisect(a as Double, b As Double, f As Function(Of Double, Double)) As Double
    Dim c As Double = (a + b) / 2 
    Dim d As Double = f(c)

    While Math.Abs(d) >= 0.0001
        If Math.Sign(d) = Math.Sign(f(a)) Then 
           a = c
        Else
           b = c
        End If    

        c = (a + b) / 2
        d = f(c)
    End While
    Return c
End Function

But VS say Keyword does not name a type.
I thing the signature is wrong.
Any advice?

[OptionBase1]

You found it online where?

[jmcilhinney]

Either the person who posted it made a mistake typing it or you did. That should almost certainly be this:

Function Bisect(a as Double, b As Double, f As Func(Of Double, Double)) As Double

An Action is a delegate for a Sub, i.e. a method that doesn't return a value, and a Func is a delegate for a Function, i.e. a method that does return a value. Both can have zero to 16 parameters. I suggest that you read the documentation for each.

[PlausiblyDamp]

Hello, I'm trying to use this method that I found online:

Function Bisect(a as Double, b As Double, f As Function(Of Double, Double)) As Double
    Dim c As Double = (a + b) / 2 
    Dim d As Double = f(c)

    While Math.Abs(d) >= 0.0001
        If Math.Sign(d) = Math.Sign(f(a)) Then 
           a = c
        Else
           b = c
        End If    

        c = (a + b) / 2
        d = f(c)
    End While
    Return c
End Function

But VS say Keyword does not name a type.
I thing the signature is wrong.
Any advice?

I suspect the declaration should be

   Function Bisect(a As Double, b As Double, f As Func(Of Double, Double)) As Double

Edit: jmcilhinney beat me to it, my own fault for having too many tabs open...

[hannibal smith]

Either the person who posted it made a mistake typing it or you did. That should almost certainly be this:

Function Bisect(a as Double, b As Double, f As Func(Of Double, Double)) As Double

An Action is a delegate for a Sub, i.e. a method that doesn't return a value, and a Func is a delegate for a Function, i.e. a method that does return a value. Both can have zero to 16 parameters. I suggest that you read the documentation for each.

Thanks. Now it work.