Question

I’ve written a function in C# that does a numerical differentiation. It looks like this:

public double Diff(double x)
{
    double h = 0.0000001;

    return (Function(x + h) - Function(x)) / h;
}

I would like to be able to pass in any function, as in:

public double Diff(double x, function f)
{
    double h = 0.0000001;

    return (f(x + h) - f(x)) / h;
}

I think this is possible with delegates (maybe?) but I’m not sure how to use them.

Answer 1

Using the Func as mentioned above works but there are also delegates that do the same task and also define intent within the naming:

public delegate double MyFunction(double x);

public double Diff(double x, MyFunction f)
{
    double h = 0.0000001;

    return (f(x + h) - f(x)) / h;
}

public double MyFunctionMethod(double x)
{
    // Can add more complicated logic here
    return x + 10;
}

public void Client()
{
    double result = Diff(1.234, x => x * 456.1234);
    double secondResult = Diff(2.345, MyFunctionMethod);
}