CSCI 201: Intro to Programming (Java)

Assignment 6.    Due: Wed, Nov 15

Please put your work in directory cs201 on your Linux account before 11:59pm of the day above.

1. (25 points)   Write the following function that reads a two-dimensional array from file hw6_1.dat (create this file by yourself and add it to the project) and tests whether it has four consecutive numbers of the same value, either horizontally, vertically, or diagonally.

   public static boolean isConsecutiveFour(int[][] a)

   Your program should print True if the array contains four consecutive numbers with the same value. Otherwise, display False. Here are some examples of the true cases:

   

   Your program must work for any array, not just for the above examples.

   Name the project Hw6_1
   Solution

2. (25 points)   Design a Java application to implement the following algorithm for sorting an array of integers. According to this algorithm, the sort is accomplished by repeatedly taking the next item from the array (pivot) and inserting it into the final array in its proper order with respect to the items already inserted.

   Example:

   Given the following array a for sorting, it is traversed just once, the position of the currently processing pivot is indicated by "^". In each step the marked pivot is inserted to its proper place in array b. The resulting sorted array is b.

       a: 14 5 7 12 8      b: (empty)
   
   step1: 14 5 7 12 8      b: 14
          ^
   
   step2: 14 5 7 12 8      b: 5 14
             ^
   
   step3: 14 5 7 12 8      b: 5 7 14
               ^
   
   step4: 14 5 7 12 8      b: 5 7 12 14
                 ^
   
   step5: 14 5 7 12 8      b: 5 7 8 12 14
                    ^
   

   Your program should contain method int[] inSort(int[]) that takes the original array (array a in the above example) as a parameter and returns the sorted array (array b in the above example). The original and sorted arrays must be printed out.

   Name the project Hw6_2
   Solution

3. (25 points)   Design a class named MyInteger. The class must include the following features:
   • A private class variable named value that stores the integer value represented by this object.
   • A constructor that creates MyInteger object for the specified int value.
   • A get method that returns the int value.
   • Methods isEven(), isOdd(), and isPrime() that return true if the value is even, odd, or prime, respectively.
   • Static methods isEven(int), isOdd(int), and isPrime(int) that return true if the specified value is even, odd, or prime, respectively.
   • Static methods isEven(MyInteger), isOdd(MyInteger), and isPrime(MyInteger) that return true if the specified value is even, odd, or prime, respectively.
   • Methods equals(int) and equals(MyInteger) that return true if the value in the object is equal to the one specified by the parameter.
   • A static method parseInt(char[]) that converts an array of numeric characters to an int value.
   • A static method parseInt(String) that converts a string into an int value.

   Implement the class. Write another class with main() method that would ask the user to enter an integer, instantiate class MyInteger based on that number, and test all methods in MyInteger class.

   Name the project Hw6_3
   Solution

4. (25 points)   Define the Circle2D class that contains:
   • Two private class variables of type double named x and y that specify the center of the circle with the corresponding public get methods.
   • A private field radius its get method.
   • A no-argument constructor that creates a default circle with (0, 0) for (x, y) and 1 for radius.
   • A constructor that creates a circle with the specified x, y, and radius.
   • A method getArea() that returns the area of the circle.
   • A method getPerimeter() that returns the perimeter of the circle.
   • A method contains(double x, double y) that returns true if the specified point (x, y) is inside this circle. See Fig. (a) below.
   • A method contains(Circle2D circle) that returns true if the specified circle is inside this circle. See Fig. (b) below.
   • A method overlaps(Circle2D circle) that returns true if the specified circle overlaps with this circle. See Fig. (c) below.

   

   Implement the class. Write a test program that creates a Circle2D object c1 (new Circle2D(2, 2, 5.5)), displays its area and perimeter, and displays the result of c1.contains(3, 3), c1.contains(new Circle2D(4, 5, 10.5)), and c1.overlaps(new Circle2D(3, 5, 2.3)).

   Name the project Hw6_4
   Solution