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 [Solved] Simple Question  (Read 1095 times) 0 Members and 1 Guest are viewing this topic.
 « Posted 2012-06-12 00:30:25 »

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?
 1  2  3  4  5  6  7  8  9  10  11  12 `//this is a method's bodyRandom 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;`
sproingie

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 « Reply #1 - Posted 2012-06-12 00:37:08 »

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.
Sickan

Senior Member

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 « Reply #2 - Posted 2012-06-12 07:14:33 »

Why do you use doubles for your for loops? I'm just generally curious why.
Riven
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 « Reply #3 - Posted 2012-06-12 07:27:43 »

 1 `if(dice.nextInt(100) + 1 < 10){`

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.

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 « Reply #4 - Posted 2012-06-12 14:13:52 »

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.
ReBirth
 « Reply #5 - Posted 2012-06-12 14:28:13 »

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