Question 1

Assume xArray and yArray are equal length arrays of int values storing num items (num is also an int). Write a paint method for an Applet that will draw a Polygon shape using this information. Assume xArray, yArray and num are all instance data of the Applet.

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Question 2

Write a method that takes an array of Strings as a parameter and the number of elements currently stored in the array, and returns a single String that is the concatenation of all Strings in the array.

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Question 3

Explain how to alter the Selection Sort algorithm so that it sorts in descending order instead of ascending order.

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Question 4

Write a method public static int[ ][ ] matMult(int[ ][ ] x, int[ ][ ] y) which accepts two matrices, x and y, and yields their product x * y as its result. Use the normal rules for matrix multiplication. Be certain to test to see that x and y are compatible before beginning to compute the matrix product.

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Question 5

Implement an ItemListener so that a new value is output by the second JLabel every time a JCheckBox is clicked on.

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Question 6

Write an insertion sort method to sort an array of String values (instead of an array of int values). Assume the array is an instance data of the current class called list, and number is an int instance data that stores the number of elements currently stored in list.

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Question 7

Write a method to output all elements of a two-dimensional array of int values as a table of rows and columns. Use "	" to get elements to line up properly. The method is passed the two-dimensional array and two int values that denote the number of both dimensions (rows followed by columns).

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Question 8

Say that you want to construct a tiny drawing program, where the objects are defined using line segments. One might use the rubber-banding ideas presented in this chapter to define the endpoints of line segments, hooking them together into a polyline. One might provide a button that turns a polyline into a polygon. If this approach is taken, what would be a good way to represent the data involved in this program: the points, the line segments, the polylines, the polygons?

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Question 9

In the RubberLinesPanel example in the text a single LineListener class was defined, implementing both MouseListener and MouseMotionListener. What are the advantages and disadvantages of this approach compared to defining two separate classesone for each kind of Mouse Events?

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Question 10

Write code to create a JPanel with 4 JCheckBox GUI components and two JLabels for output, one that says "Current cost is" and the other that outputs the computed cost based on which of the food items has been selected.

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Quiz 8: Arrays