CODEWITHSUNDEEP
javamathif-statementrandomdouble
user2328614
user2328614

Reputation:

Randomize when something happens

I have implemented a power up in my game and I want it to have an 10% chance to apply to the player when it kills a zombie. I have tried using this code every time the players bullet hits an zombie, but it doesn't really work.

double rand = Math.random() * 10 + 1;
if(rand == 1){
    power.setShrink(true);
}

I know that the power-ups work because if I set it outside of the if-statement the player will get shrunk.

How would I make it so that it's an 10% chance for the effect to apply the player when a zombie get killed?

Upvotes: 1

Views: 77

Answers (3)

Antimony
Antimony

Reputation: 39451

Doubles are floating point numbers. In you case, it can be any number from 1 to 11, up to around 53 binary digits of precision. So not only can it be 1, it can also be 1.01, 1.02, etc. Te odds of it being exactly 1 are therefore negligible.

You're better off with Random.nextInt when generating random integers.

Random r = new Random(); //only do this once

if(r.nextInt(10) == 0){
    power.setShrink(true);
}

Upvotes: 2

Duncan Jones
Duncan Jones

Reputation: 69339

You could use Random.nextInt(10) in a similar piece of logic.

Your current code is failing because your double is very rarely going to be exactly 1.

Upvotes: 0

IsNull
IsNull

Reputation: 676

You can use a simple Monte-Carlo selection:

if(Math.random() > 0.9){
   power.setShrink(true);
}

This gives you a random chance of the possibility 1 of 10 that it will trigger the power-up.

Upvotes: 1

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