Seeding a PRNG - Custom Setter

Question

I have a PRNG-Class called Generator. Now, after creating a new instance of it:

var g:Generator = new Generator();

Custom function: set_seed() - Please review this approach.

I call g.set_seed(); which has the following logic:

public function set_seed(s:Number = 0):void
{
    seed = (s > 0) ? s : new Date().getTime();
}

• Pro: I can call it without any arguments, looks more beautiful in the classes I'm using it.
• Con: set_seed looks awful and I feel I should be using Flash's Getter/Setter approach.

(I'm getting the seed with: get_seed();)

Answer 1

I would expect the generator to seed itself (using the current time) in its constructor.

Therefore, I would not use a default parameter in your set_seed method.

Also, in your current code, you treat all the negative values the same as zero. I wouldn't recommend that. Many random seeders can handle negative seeds as well, if you don't want to do that: Throw an Exception/Error!

Therefore, I would use this:

public function set_seed(s: Number): void
{
    if (s < 0) {
        throw new Error("Seed must be positive");
    }
    seed = s;
}

For comparison and inspiration, check Java's java.util.Random class. Note that it has two constructors available, one for initializing to System's seed and one for initializing to a specific seed. That is an approach I would recommend.