CS46A Fall 19

8A

Complete the class ColoredCircles. A ColoredCircles represents a drawing of circles with 5 rows and 4 columns in random colors. It has a constructor that takes (x, y) location of the upper left hand corner of a set of circles and the diameter of the circles

Use the Ellipse class from the Horstmann graphics.

Provide a constructor that takes the (x, y) coordinates of the upper left hand corner and the diameter of the circles as parameters. Do not draw in the constructor

Provide the methods

• draw() which fills 5 rows each containing 4 circles. Use the constants given in ColoredCircles . Each circle is filled with a random color either red, blue, green or black. You will write a getRandomColor method to figure out the color to use. Iterate through the rows in the outer loop and through the columns in the inner loop. That means you will draw the first row, then the second, etc.
• getRandomColor() gets a random color, either Color.RED, Color.BLUE, Color.GREEN, Color.BLACK. You are provided with a Random object. Use it and do not change the seed. Generate a random integer 0, 1, 2, or 3 and use the constants defined for you to determine the color. For example if the random number is RED (0) the method will return Color.RED

Other instructions

• You must use nested loops
• You must use the constants defined

Your output for the final will look like this.

For the draft, complete the constructor. Implement the draw method to draw the first row all in red. This is essentially the inner loop. You must use a loop.

8A draft:
8A final:

8B

Create an application called DogList with a main method. In the main method, do the following

• Create an ArrayList of Strings
• Add "Pit Bull" , "Collie", "Irish Setter", "Rottweiler",  "Boxer" in that order.
• Add "Siberian Husky" at position 2
• Replace the element at index 3 with "Great Dane" Use the set method
• Replace the next to the last element with "Malamute". Do this in a manner that would replace the next to the last element, no matter the size of the array list. Think about how to find the last element in an array list, then find the index of the next to the last element and use the set method. Don't just use 4 in the set method
• Remove "Pit Bull" (see Note1 below)
• Get and print the the element at index 2 followed by "***"
• Print the elements on one line in the [xxx, yyy, ...] format. (See Note2 for an easy way to do this .Do not use a loop)
• Print the entire array list one element to a line (use the enhanced for loop)

Note: You must use an ArrayList and its methods. Do not fake it by just printing the correct strings. You will need to know how to use these methods in a situation where the output can not be faked.

Note1: There is a version of remove method that will remove a specific object. Use that. Here is the code to remove target from the ArrayList called stuff

stuff.remove(target);

Note2: To print an ArrayList in the [xxx, yyy, ...] format, use its toString method like this

System.out.println(stuff.toString());

8B draft:
8B final:

8C

Write an EllipseManager class which manages Ellipse objects.

Use the Ellipse class from the Horstmann graphics library.

The EllipseManager has an instance variable ArrayList<Ellipse>. Call the instance variable list. It has a no-argument constructor (That means it takes no parameters) which initializes an ArrayList of  Ellipses to an empty ArrayList.

Provide these methods

• public void add(Ellipse e) adds this Ellipse to the EllipseManager (adds it to the ArrayList instance variable)
• public void exchange(int index1, int index2) - swaps the element at index1 with the element at index2. If either index is out of bounds, do not changing anything.
• public Ellipse largest() gets the Ellipse with the largest area. If more than one Ellipse has the same area, return the first. If the EllipseManager is empty, return null. The image below shows the formula for the area of an Ellipse
• public String toString() gets a string representation of the ArrayList - provided. (This is why the instance variable must be called list.)

From Google.com:

Provide Javadoc

For the draft, define the instance variable and implement the constructor. Also implement the add method.

8C draft:
8C final: