Assignment

Cameron said... Here's an assignment for you. This is important to do, because it will really hit where you're getting frustrated - working with methods, both creating them and passing values to them. Give it a try!

I didn't compile the code in the examples, so you might want to make sure I haven't missed a semi-colon or anything. Regardless, the objective remains the same: create the methods that I've asked for, and write some code that invokes the methods by passing in the appropriate objects! This will be eye-opening for you.

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Let's look at three core shapes: Circle, Point and Rectangle.

Here's how we create them:

Circle drum = new Circle(2);

Circle life = new Circle(10);

Point ed = new Point(0,0);

Point pelee = new Point(5,5);

Rectangle r1 = new Rectangle(2,3);

Rectangle r2 = new Rectangle(5,4);


If I wanted to just print out the area of a Circle, I could create a method like this:

public class PracticeMethods {
public void printCircleArea(Circle c) {
System.out.println("The area of the circle you passed me is: " + c.getArea();
}
}

To run this code, I could write a class like this:

public class PMRunner {

public static void main(String args[]) {
Circle drum = new Circle(2);
PracticeMethods pm = new PracticeMethods(); //create an instance
pm.printCircleArea(drum); //pass an instance of a Circle to the method.
}

}

When the PMRunner executes, it will print out: The area of the circle you passed me is: 6

So, here you see how to code a class that has a method that takes an argument. (The PracticeMethods class)

And you also see how to create an instance of a class, and call one of the instance methods, while also passing in an argument of the proper type.

Question: Why does the printCircleArea return void and not a String? Doesn't the method return a String?

In the PracticeMethods class, create the following methods:

compareCircleToCircle - it takes two circles as arguments. It returns true or false depending on whether the two circles have the same area.

comparePointToCircle - it is passed in a Point and a Circle. It prints out how much bigger the area of the circle is than the area of the point.

compareCircleToSquare - it is passed in a Circle and a Square. It returns a String that says "The circle is bigger than the square" or "The square is bigger than the circle" or "The circle and square are the same size."

compareSquareToSquare - it is passed in two Squares, and returns a boolean value indicating if the first square is bigger than the second. It also returns the difference in the sizes of the two squares.