Stop Random()

Programming Questions

mentecode

in Programming Questions • 6 months ago

Hello all.

I've been recently trying to develop a random direction generator "prototype", and an issue comes up.
No exception, but rather the program isn't doing what it's supposed to do.

I want to stop the random() function/action for generating more numbers in this code:

int r = 2;
byte dir;
while (r > 1) {
dir = byte(floor(random(4)));
r = 0;
println(dir);
}

Nothing complicated, but the program continuously prints out a random number, when it should've stopped.
Why is it doing that?

- MenteCode

Replies(15)

println_h..

Re: Stop Random()

6 months ago

1. Is this code the function itself?

2. if so you might want to just make it:

void randomDir()

{

dir = byte(int(random(4))

}

OR:

int randomDir()

{

return int(random(4));

}

3. if the function name is Random, call it something else like randomDir, do you dont get it confused with random()

4.Use int() instead of floor(), because there is an EXTREMELY small chance that you will get a direction of 3, because the rendom function has to return 4, not even 3.99999 so there are WAY more ways to get anything but 4 than there are to get 4.

mentecode

Re: Re: Stop Random()

6 months ago

I think you're missing the whole point of my question. I'm pretty good at debugging (not to brag), so this does not answer the question.

There is going to be a lot more in the function than just random. This question is just for the end of the function, so it stops generating numbers. Otherwise, it might throw an exception, due to repetition.

- MenteCode

asimes

Re: Stop Random()

6 months ago

For me, this exits after printing one number:

void setup() {
size(100, 100);
int r = 2;
byte dir;
while (r > 1) {
dir = byte(floor(random(4)));
r = 0;
println(dir);
}
exit();
}

It may be worth pointing out that you can end the loop at any point by writing this:

void setup() {
size(100, 100);
byte dir;
while (true) {
dir = byte(floor(random(4)));
println(dir);
break;
}
exit();
}

PhiLho

Re: Stop Random()

6 months ago

" I think you're missing the whole point of my question."
I don't think so...
You show a function that uses a loop designed to exit immediately after running its content, so he shows a similar function doing the same thing, only simpler...
You simplified your code, which is a good thing (but you should mention it, so we don't judge code on such demo), but apparently you simplified it too much (you should test the simplified code too...), because without even running it, it is obvious that it doesn't do what you say.

mentecode

Re: Re: Stop Random()

6 months ago

Let me get things straight, just to make sure I didn't miss anything.

I want to make a piece of code (not a function), that could generate a random number once, until it is called again. I would like to put this piece of code into a function called from draw().

This function must execute in a loop, like it usually does, but i want the random to stop generating numbers, without having the entire function stop, and print one number in the console.

The problem is that I don't want to make a separate function, just for the generation of one number.
If there's no way (which I doubt there isn't), I could go with making a separate function, and call it every time I need a new number.

- MenteCode.

PhiLho

Re: Stop Random()

6 months ago

" I could go with making a separate function, and call it every time I need a new number."
It is probably the simpler and cleaner way to make it. Don't hesitate to make a function, even for a one-liner. It is common practice, and useful, as it modularize the code.
" i want the random to stop generating numbers"
Yes, that's what I found odd in your title and message. Usually, you don't ask a function to stop functioning, you just stop calling it.

mentecode

Re: Re: Stop Random()

6 months ago

As of now, I still haven't quite got used to calling functions with parameters, and I get the feeling that I would have to use this method, annoying as it is to me. I guess it's worth a shot.

- MenteCode.

asimes

Re: Stop Random()

6 months ago

Maybe just use a conditional in the function to produce the random number whenever you need it? Like this:

myFunction() {
//...code
if (someCondition) dir = byte(floor(random(4)));
//...code
}

mentecode

Re: Re: Stop Random()

6 months ago

So, if I wanted to have the number displayed once, I would have to immediately make the condition false?

- MenteCode.

asimes

Re: Stop Random()

6 months ago

I'm guessing because I don't know the structure of your program, but sure that probably would work. Whenever you need another random number just make it true and it will turn itself off again.

if (condition) {
dir = byte(floor(random(4)));
condition = false;
}

GoToLoop

Re: Stop Random()

6 months ago

I can't figure it out what you're asking!
If you don't want random() to keep generating random numbers, why don't you just save its last picked one?

Anyways, I've made a static class (no need to instantiate it) to emulate a random "freezing".
Just call StopRandom.stop() ; and after that, StopRandom.rand() will only return last random number!

// http://forum.processing.org/topic/stop-random

void setup() {
  int a;

  for (int i = 0; i != 8; i++) {
    a = StopRandom.rand(-5, 10);
    print(a + "\t ");
  }

  println( "\n" + StopRandom.toggle() );

  for (int i = 0; i != 8; i++) {
    a = StopRandom.rand(-5, 10);
    print(a + "\t ");
  }

  println("\n" + StopRandom.lastPick);

  exit();
}

static final class StopRandom {
  static double  lastPick;
  static boolean isFrozen;

  static float rand() {
    return isFrozen? (float) lastPick : 
    (float) ( lastPick = Math.random() );
  }

  static float rand(float maxRange) {
    return maxRange < 0? rand(maxRange, 0) : rand(0, maxRange);
  }

  static float rand(float minRange, float maxRange) {
    return isFrozen? (float) lastPick : 
    (float) (lastPick = Math.random() * 
      (maxRange - minRange) + minRange);
  }

  static int rand(int maxRange) {
    return maxRange < 0? rand(maxRange, 0) : rand(0, maxRange);
  }

  static int rand(int minRange, int maxRange) {
    return isFrozen? (int) lastPick : 
    (int) (lastPick = Math.floor( Math.random() * 
      (maxRange - minRange) ) + minRange);
  }

  static void stop() {
    isFrozen = true;
  }

  static void start() {
    isFrozen = false;
  }

  static boolean toggle() {
    return isFrozen = !isFrozen;
  }
}

mentecode

Re: Re: Stop Random()

6 months ago

Yeah, I'm not good at asking simple questions.

It's a little long, but I guess that it makes sense. Now with three ways to do the same thing, it would be very useful to know what to use where. I'll figure that out later.

- MenteCode.

mentecode

Re: Stop Random()

6 months ago

Thanks for all the responses.

I'm aware that the majority of you didn't quite understand what I was saying.
Don't mind me.

Thanks again,
- MenteCode.

boub_pops..

Re: Re: Stop Random()

6 months ago

Having read eveything, may be you have to be aware that the draw() function runs forever ... unless you use the noLoop() method ...

May be that was your question ...

GoToLoop

Re: Stop Random()

6 months ago

It's a little long, but I guess that it makes sense.

From my class example, only these methods below are necessary to emulate random():

```
static float rand(float maxRange)
```

static float rand(float minRange, float maxRange)

You can always access fields isFrozen & lastPick directly anyways!

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