Random int that is different to the previous one

Unity Engine
1

Ok,

I am trying to generate an integer (Between 1 and 3) that never has the same number in a row, IE never generates consecutive numbers.
I realise this is a fairly basic thing to ask, but I really am having some trouble. My current script, which freezes unity:

#pragma strict

var num : int = 0;
var oldNum : int = 0;

	while(num == oldNum)
	{
	num = Random.Range(1,4);
	oldNum = num;
	}
	
function Update()
{
Debug.Log(num);
}

Help?

2

Your loop sets oldnum to num before it goes to the while again, causing a lockup as it never leaves the loop.
Change to this…
Int lastnum = 0;
Do
{
num = random.range(1,4);
} while (num != lastnum);
Lastnum = num;

Soz typed this in on the ipad so make sure yu get the cases correct.

3

It is freezing because it can never escape from the while loop:

//while still the oldNum keep changing.  So lets say oldNum is 2
while(num == oldNum){
     num = Random.Range(1,4); //And now this is set to 3
     //Yay we are no longer the same as oldNum!... oh wait 
     oldNum = num; //And here oldNum is changed to num again.  So since oldNum and num are the same again we have to loop again... forever
}

You should set oldNum to num, OUTSIDE the loop:

while(num == oldNum){
     num = Random.Range(1,4);
     //inside
}
oldNum = num;//outside

Edit:
Aww drat, you beat me to it arkon. But mine looks prettier. :wink:

4

Well have you tried typing in a code example on an ipad? Lol. Took me ages to find a squiggly! Oh an your conditions and statements are in light blue, and everyone knows dark blue looks better, and as for green comments… Well nuff said. Oh and calling a variable oldnum is very ageist!

5

Thanks guys, changed it to this:

#pragma strict

var num : int = 0;
var oldNum : int = 0;

	while(num == oldNum)
	{
	num = Random.Range(1,4);
	}
	oldNum = num;
	
function Update()
{
Debug.Log(num);
}

But this just makes it repeat a number indefinitely… help?

6

You are calling “Debug.Log” in Update. Update happens every frame, so it would post that message every frame; Execution Order of Event Functions.

You should probably just put this all in a single function so you can call it when needed:

#pragma strict

var num : int = 0;
var oldNum : int = 0;

function NewNum(){
     while(num == oldNum){
     num = Random.Range(1,4);
     }
     
     oldNum = num;
     Debug.Log(num);
}

Then just call “NewNum” whenever you want to change num.

@arkon
No actually, but have on a phone so I can relate haha.

7

Fixed it, had to move while loop to update.

#pragma strict

var num : int;
var oldNum : int;

	
function Update()
{
Debug.Log(num);

	while(num == oldNum)
	{
	num = Random.Range(1,4);
	}
	oldNum = num;
	
}
8

Oh, well, I guess that works for you too. >_>

9 
var max:int;
var oldNum:int = -1;

// Generate a number between 0 and max - 1
function NewNum():int {
  var result = Random.Range(0, max);
  if (result == oldNum) result = (result + Random.Range(1, max)) % max;
  oldNum = result;
  return result;  
}