[Solved] Simple Question

Newbie & Debugging Questions
#1

Hi, I want to crunch some numbers with Java and I’m going to be testing Crit Chance (a %chance on hit that you’ll deal x times more damage).

Does the code below correctly simulate someone attacking 1 million times with 100 damage and a 10% chance to crit for 300% damage?

//this is a method's body
Random dice = new Random();
double total = 0;
double damage = 100;
for(double i = 1; i < 1000000; i++){
	if(dice.nextInt(100) + 1 < 10){
		total += damage * 3;
	}else{
		total += damage;
	}
}
return total;
#2

Looks right to me. Just split out the meat of the loop into a method and it’ll even look obviously right.

Rule #1 of simulation: do it once, repeat it 999999 more times.

Rule #1000000 of simulation: do it once, repeat it 0 more times.

#3

Why do you use doubles for your for loops? I’m just generally curious why.

#4

dice.nextInt(100) gives you 100 distinct values: 0…99, you turned that into 1…100.

If you count the number of values that are smaller than 10, you get: 1,2,3,4,5,6,7,8,9 (nine numbers)

So your code actually calculates the results for 9/100 (9%) chance to cause 300% damage.

Just remove the +1 and you’re fine.

#5

Sproingie: Thanks for the feedback x).

Sickan: I use double’s because at times I’d want to calculate 175% crit and that number would get rounded as an int.

Riven: Thanks! That’s the part of the code that was bugging me.

#6

No, he did mean why you use double for ‘i’, which is unused inside the loop.

#7

Ah valid point, I’ll switch that to int then. I originally had my code all in int and did a Ctrl+f replace all int with double and forgot to check it over after doing that, thanks.