How to develop a type ?

you mean a class?

public class AskBetterQuestions {

public AskBetterQuestions (){

}

}

mkoryaka at 2007-7-8 2:22:58 >

> How to develop a type ?

By designing it first. On top of that you don't go "ok, I want to develop a type T".

There should be a need for that type T. What do you want to 'say' to that

T thing; what do you want a T thing to return to you? What are its tasks

(responsibilities) and what can it rely on? What do you have to feed a T

in order to make a T survive? How should that T defend itself against

malicious attacks (read: incorrect invoking code)?

This is the fun part because you can design a T in a horizontal position

without having to use such a nasty computer. All you need is your brains

and a bit of scribbling paper.

kind regards,

Jos

JosAHa at 2007-7-8 2:22:58 >

> > I know your code is just an example, but I'd suggest

> > primitives for re and im. That is, lowercase "d" on "double".

>

> Why?

I don't see a need to have them as objects. The re and im parts will always have a value (might be zero, but that's still a value). No need to handle "null" [yes, if you make it immutable, and set up the constructors correctly, you can avoid any "null"--but primitives and "zero" is easier]. Even with autoboxing, why store Double objects? You'll have to convert to primitives to do 'getMagnitude', 'getAngle', 'multiply', 'divide', 'add', 'subtract', or anything else, and would need to convert back to Double objects to create the new Complex object. So, storing as primitives seems more straightforward.

doremifasollatidoa at 2007-7-8 2:22:58 >

> > I don't see a need to have them as objects.

>

> I can think of several reasons to have the members as

> objects (e.g, BigInteger, with an option to represent

> the value as a BigDecimal), especially if accuracy is

> a concern. These reasons also encapsulate why the

> choice of double may not be a good idea for a

> particular situation.

Okay, I'll accept that argument. For more scientific purposes, that argument sounds fair to me. For an implementation used to teach programming, I think double will suffice (maybe the professor could then have a discussion as to what you could do if you needed more accuracy for your computations).

doremifasollatidoa at 2007-7-21 16:11:29 >

> Sounds good to me. Thanks for your amicable response.

You're welcome. I see no reason to fight on something like this. You had a good point. "Double vs. double" doesn't make a difference accuracywise (as far as I know), but BigDecimal could make a difference. BigDecimal and Double obviously do make a difference accuracywise.

Cheers to you, too!

doremifasollatidoa at 2007-7-21 16:11:29 >

> <not so amicable nitpick>

> That's why the Number class nilfisks big times. It ties any concrete

> number to a primitive type and all the descendents thereof.

> <not so amicable nitpick/>

It all depends on the pedagogical target. I don't see a problem with using primitives for introductory instruction. As mentioned, I think there are practical reasons to *not* use them for more critical applications.

Nitpick noted.

yawmark (<-- original nitpicker)

~

yawmarka at 2007-7-21 16:11:29 >

> > No, I was first! *beep!* *beep!* *beep!*

>

> What ho, varlet, dost thou go cross-gartered?

>

> *beep!* *beepity!* *beep!* *beep!*

>

> Ha-HA!

Nonononono! How many times do I have to tell you that there are no

"beepeties" allowed in the gigue (nor the entree nor bouree) of the duel!

When will you ever learn, you barbarian.

Now, once again: *beep!* en garde *beep!*

kind regards,

Jos ;-)

JosAHa at 2007-7-21 16:11:29 >

> > Now, once again: *beep!* en garde *beep!*

>

> *beepity!* *beepity!* *beepity!* (<-- double-bladed)

>

> Ha-HA!

No grasshopper; you don't want me to alert the grand jury do you?

Beepeties are not allowed until the allegro of the duel. Remember that.

Now, for the third time: *beep!* (slowly now, slowly) *beep!* *beep!*

(yes, assume the position) *beep!* (advance now, but slowly) *beep!*

See? that's the way it's supposed to go; no plebeian beepeties and stuff ;-)

kind regards,

Jos

JosAHa at 2007-7-21 16:11:29 >