CODEWITHSUNDEEP
java
Taylor Dawson
Taylor Dawson

Reputation: 11

Custom Dice Generator

Okay so this is for homework. I don't want a complete answer, just someone to help nudge me in the right direction. I am fairly new to Java, so please take it easy :P Okay so my professor is having us do a Dice simulation program with OOP. This is just one portion of the entire problem, but it's the part I'm stuck on, so if you need more I can provide more. But the instructions say:Make a Roll function that will simulate rolling each die, and return the total This function should only allow values between the appropriate range (i.e. if each die only has 4 faces, only numbers 1 - 4 should be allowed). What I have so far for this particular function is this:

public double Roll()
{
    for(int i = 0; i < numDice; i++)
    {
    double total = Math.random()*numFaces + 1;
    }
    return total;

I don't know where to go from here, and I don't know what really to do. This is my first programming class and it's way over my head :P So like I said, if I could just get pointed in the right direction (using dummy talk, cause I'm still having a hard time grasping this whole thing) that would be awesome. And I can provide more of the actual problem if need be.

Upvotes: 0

Views: 599

Answers (5)

Dev
Dev

Reputation: 12206

You could create a class named Die to represent a die. This fits with OOP as 'die' would be one of your nouns. Now think of what configuration and behavior a Die might have. You may wish to have a Die have a configurable number of faces, but default to 6 if it isn't specified. You also want to be able to roll a die. Lets see what we have so far. Implementation left up to the reader.

public class Die {

    public Die(){
        this(6);
    }

    public Die(int faces){
        //TODO: Write a constructor that takes number faces as an argument.
    }


    public int roll(){
        //TODO: Implement a roll for this die, considering the number of faces.
    }

}

Ok, so you have the beginning of a Die class. Now you might think, wouldn't it be cool if I could group die together as Dice (a set of dice if you will).

public class Dice { 

    public Dice(Die... dice){
        //TODO: Implement constructor that takes an array of die objects.
    }

    public int roll(){
        //TODO: Roll all the dice, sum and return the result.
    }
}

Next you might think, man wouldn't it be sweet if I could treat Dice and a single Die as a single type, I mean they both can be rolled. Let us create an interface called Rollable that specified the roll behavior and have both Dice and Die implement it.

public interface Rollable {

    int roll();

}

Then go back and change the class declarations to be.

public class Die implements Rollable

and

public class Dice implements Rollable

Now code that needs to roll things only needs to worry about Rollable instead of Die or Dice

Upvotes: 1

Zeveso
Zeveso

Reputation: 1294

Just noticed you used double , replace double with int or short. Look at the following tutorial.

http://docs.oracle.com/javase/tutorial/java/nutsandbolts/datatypes.html

Your also not so hot with naming conventions. Read this.

http://www.oracle.com/technetwork/java/javase/documentation/codeconvtoc-136057.html

You don't need to roll for each face, only for each dice. Do this.

Please note, for this you could use shorts as well.

public int roll() {
    return new Random().nextInt(6) + 1; // Returns number between 1 and 6
}

If you want to roll multiple dice you could do this.

public int roll(int amount) {
    int total = 0;
    for(int i = 0; i < amount; i++) {
        total += new Random().nextInt(6) + 1;
    }
    return total;
}

Upvotes: 2

kviiri
kviiri

Reputation: 3302

You're defining total inside the for loop, which makes it invisible outside it. Also, you're overwriting it (=) instead of adding to it (+=) on each die throw.

public double Roll()
{
    double total = 0;
    for(int i = 0; i < numDice; i++)
    {
        total += Math.random()*numFaces + 1;
    }
    return total;
}

I would also recommend to follow Java style and rename the method roll (methods start with a lowercase letter). The return type also strikes me as odd, I would probably use int in a similar situation.

Upvotes: 1

David Brossard
David Brossard

Reputation: 13834

You need to define total outside the for loop and then do total+=… inside the loop

Upvotes: 0

Simon Forsberg
Simon Forsberg

Reputation: 13351

First of all, you need to declare the total outside the for-loop. Then initialize it to zero.

Then, inside the for-loop. Increase the variable.

If numFaces should be able to be different for each die, you will need to get the value for it inside the for-loop, on each iteration.

Also, you should ask yourself: Which possible values do I want for the total variable? Should it be int or double?

Upvotes: 0

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