1 divided by 2 = 0?

Archived Forums Questions & Answers
1

ok so as soon as i press “p” to increase the difficulty, difficulty increases to 2 and the timer sets to 0. i already tried making it a float but that didn’t change anything?

var xPos : float = Random.Range(-50,50);
var yPos : float = Random.Range(-50,50);
var zPos : float = Random.Range(69,9001);
var spawnPos : Transform;
var spawnObject : GameObject;
var timer : float = 1;
var difficulty = 1;
var score = 0;
var countScore = 1;

function Start () {
Invoke("CustomUpdate",timer);
}

function CustomUpdate () {
Invoke("CustomUpdate",timer);
xPos = Random.Range(-50,50);
yPos = Random.Range(-50,50);
zPos = Random.Range(69,9001);
spawnPos.position.x = xPos;
spawnPos.position.y = yPos;
spawnPos.position.z = zPos;
Instantiate(spawnObject,spawnPos.position,spawnPos.rotation);
if(countScore == 1){
score += 1;
}
}

function Update () {
if(Input.GetKeyDown("o")){
if(difficulty >= 2){
difficulty -= 1;
}
}
if(Input.GetKeyDown("p")){
if(difficulty <= 9){
difficulty += 1;
}
}
timer = 1 / difficulty;
}

function Message () {
countScore = 0;
}

function OnGUI () {
GUI.Label (Rect (10, 10, 200, 40),"score:" + score);
GUI.Label (Rect (10, 60, 200, 40),"difficulty" + difficulty);
}

Don't declare fields as 'var', limited that for being snazy inside functions. It will help you avoid doing logical mistakes. Now you have to 'guess' (since you seem unsure) what type of the result '1 / difficulty' will be. It is a int div by an int, the result will be an int. Hence, 0.

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3 Answers

3
2

if you are doing division with int, the result will be round down, so 1/2 is 0.5 and it will be round down to 0.

To get the 0.5:

var timer : float = 1; //You got this right    
...
//This will do, I think
   //Embarassing mistake
   timer = ( 1 * 1.0f ) / difficulty;

   //A better correction
   timer = 1.0f / difficulty;

Ha make it timer = 1.0f / difficulty; :D

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This is very embarassing, I was thinking in: floatNumber = intVariable / intVariable; so I make the correction to be: floatNumber = ( intVariable * 1.0f ) / intVariable;

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I am wondering, why do you have to write (1.0f) when you can just do it (1.0) and Unity will still know, that it's a float value? Does that "f" helps Unity to calculate it faster or something?

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In UnityScript 1.0 is considered as float while in C# it is a double. So in C#, we need to type 1.0f to make it a float. Whether you write 1.0 or 1.0f doesn't matter in UnityScript.

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3

you just have to make the 1 a float:

timer = 1.0 / difficulty;

4

First off you never specified difficulty as an float value. Since it had no decimal Javascript automatically makes it a Integer. With Integer values and division what happens is something called “truncating”.

Sure, it knows that 1/2 = 0.5 but that isn’t a Integer value. Ints are only concerned with the left side of the decimal. So the result is that the .5 is dropped and the 0 is returned.

Both solutions above are perfectly fine, but I also wanted to elaborate why this occurs. Be careful, this happens for all mathematical operations for ints, and ints have range of ~-2 billion something to ~2 billion something.