Random Number 1/40 Chance

How could I make something occur on a 1 out of 40 chance, I'm using this for dropping mob heads at a 2.5% chance and I can't figure out how to make this happen at this 1/40 chance.

 

AstramG
Create a random number generator that goes to 39 (because it starts from 0)
Then say:

Code:java

if ("that random number" == 1){
//do something
}

 

you could do a switch statement so it's not like if else if else if else if else if

 

Code:

Random r = new Random();
int rand = r.nextInt(41);
if (rand == 33) {
 Do stuff...
}

Rand will be a number between 0-40 (0 and 40 included). You can take any number, I just did 33

 

Well, I understand the approach but I'm a bit confused on creating a random number generator, assistance in creating one would be nice

Ah, thank you, but just for understanding why is nextInt 41? Why not 40?

EDIT by Moderator: merged posts, please use the edit button instead of double posting.

 

He explained it already

 

AstramG look at my post
EDIT: nextInt will generate a number between 0 and arg-1. So nextInt(2) will give a number between 0 and 1 with 0 and 1 included

 

No if you want a 1/40 chance, just use 39 there, because a number generator goes from 0 to <a choosen number>, 0 included, so use 39

 

TomTheDeveloper molenzwiebel
You're all wrong.
You use randomGenerator.nextInt(40). That generates 40 numbers. It starts at 0, it ends at 39.
So you don't use .nextInt(39), because it only gives 39 numbers, and you don't use .nextInt(41) either, because it gives 41 numbers.

 

Clean and simple way:

Code:

int n = 1 + (int)(Math.random() * 40);
            if(n == 1){
//Do Stuff >:D
}

 

Rprrr
Oh, sorry then, I was wrong, sorry

Thx to correct me