Aroma 2: The Die Class

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Aroma 2 The Die Class

• Special Topics Java

Dr. Tim Margush Department of Mathematics and
Computer Science The University of Akron
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Dice Rolling

• A Die commonly has 6 faces
• Faces are numbered 1 through 6
• When rolled, each face is equally likely to
  appear on top (a fair Die)
• We want to simulate a fair Die with an arbitrary
  number of faces
• We will number the faces 1 through n

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java.util.Random

• class Random
• Used to create Random objects
• Each Random object is able to produce a stream of
  pseudorandom numbers
• Seed?
• new Random() vs new Random(x)
• Methods nextInt(), nextLong(), etc.

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A Class to Die For

• import java.util.Random
• public class Die
• static private long nextSeed
• new Random().nextLong()
• private int sides
• private Random theDie
• ...

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Die Constructor, Die!

• Die(int sides)
• if (sideslt1) sides6
• this.sidessides
• theDienew Random(nextSeed)
• nextSeedtheDie.nextLong()

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Roll Die! Roll!

• public int roll()
• int rand Math.abs(theDie.nextInt())
• return rand sides 1

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Die Test Class

• import Die
• public class DieTest
• public static void main(String args)
• Die d1 new Die(6)
• Die d2 new Die(6)
• for (int i1 ilt20 )
• System.out.println("d1 "
• d1.roll()" d2"d2.roll())