Overloading vs Optional Parameters... why?

[peridian]

This is more of a general question, but I didn't know where to post it. Since Java is an example of a language which does this, I thought here would work.

Coming from a C++ background, having used VBA/VB6 quite a bit, and a number of scripting languages with similar traits, like php, I had grown accustomed to optional parameters in my functions.

I recently found out that certain modern languages do not support these, namely Java and Visual C# .NET.

This threw me at first, and then I noticed that everybody was banging on about using function overloading to provide multiple combinations of possible parameter inputs.

Now, this to me seems like incredible code repetition/redundancy, and makes things far messier (substitute longer/more complex/less elegant as you see fit) than neceesary.

I've seem a few comments about how people find the definition of optional parameters confusing. I don't know if its just because I've learned to program based on a language which supports them that I do not find this to be the case.

I've also seen some comments that it is to enforce the use of overloading for the purpose of optional parameters.

My question is quite simple: why? What is the rationale behind this method over the optional parameters?

I wondered if there was some technical gain from this approach. Or perhaps it eliminates some major source of common errors, perhaps caused by ambiguities relating to optional parameters. Or maybe it is felt that nowadays you should not have functions with a lot of parameters in anyway, so that making them optional won't involve much repetition.

I haven't been able to find a straight answer to this. I cannot believe that it is to make things easier to understand, as given the choice, I would take the C++ optional parameters over having loads of variations of a single function.

If anybody has a common sense answer to this, or insight into the decisions behind modern language definition, please do let me know.

Regards,
Rob.

[r035198x]

This is more of a general question, but I didn't know where to post it. Since Java is an example of a language which does this, I thought here would work.

Coming from a C++ background, having used VBA/VB6 quite a bit, and a number of scripting languages with similar traits, like php, I had grown accustomed to optional parameters in my functions.

I recently found out that certain modern languages do not support these, namely Java and Visual C# .NET.

This threw me at first, and then I noticed that everybody was banging on about using function overloading to provide multiple combinations of possible parameter inputs.

Now, this to me seems like incredible code repetition/redundancy, and makes things far messier (substitute longer/more complex/less elegant as you see fit) than neceesary.

I've seem a few comments about how people find the definition of optional parameters confusing. I don't know if its just because I've learned to program based on a language which supports them that I do not find this to be the case.

I've also seen some comments that it is to enforce the use of overloading for the purpose of optional parameters.

My question is quite simple: why? What is the rationale behind this method over the optional parameters?

I wondered if there was some technical gain from this approach. Or perhaps it eliminates some major source of common errors, perhaps caused by ambiguities relating to optional parameters. Or maybe it is felt that nowadays you should not have functions with a lot of parameters in anyway, so that making them optional won't involve much repetition.

I haven't been able to find a straight answer to this. I cannot believe that it is to make things easier to understand, as given the choice, I would take the C++ optional parameters over having loads of variations of a single function.

If anybody has a common sense answer to this, or insight into the decisions behind modern language definition, please do let me know.

Regards,
Rob.

You want to read about varargs in Java