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MarkStPauls
MarkStPauls wrote ...

2012/9/4

Using your introduction to Greenfoot book...compilation error occurs

MarkStPauls MarkStPauls

2012/9/4

#
Hi, Started teaching Java in Greenfoot and wanted to do the simple adaption to modern crab where you type: move(); I save the change and do a compile and an error comes up "method move in class greenfoot.Actor cannot be applied to given types; required:int; found:no arguments; reason:actual and formal argument list doffer in length" I assume there is something wrong with my install, or I am missing something elementary. move as far as I can see takes no arguments nor does it return any variable??? Does anyone have a solution?
MatheMagician MatheMagician

2012/9/4

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move() does take an argument. You need to say something like move(5);.
nccb nccb

2012/9/5

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There's two different crab projects. The modern crab is the updated one, adjusted to the latest Greenfoot API. The book uses a slightly older project, called little-crab (available in the book scenarios) where move is a method in the Animal class. If you want to follow the book, I'd use the book scenario (little-crab).
Gevater_Tod4711 Gevater_Tod4711

2012/9/5

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public void move(int length) {
        double angle = Math.toRadians( getRotation() );
        int x = (int) Math.round(getX() + Math.cos(angle) * length);
        int y = (int) Math.round(getY() + Math.sin(angle) * length);
        setLocation(x, y);
    }
This is the move method from Crab. If you've got this method you easily can change it so that it works just like you want.
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