Unit #7: Programming Assignment#9

Total Points: 15

NOTES:

· Each question is worth 7.5 points

· Your programs should be adequately documented.

Problem #1:

Write programs to implement the following:

1) Circle.java implements a class to represent a circle (see private variables and public methods below)

2) CircleTest.java creates an instance (or object) of the Circle class and calls all the public methods (see program output below)

Private Variables:

The class will contain three integer private variables – x, y and r:

· x represents the x coordinate of the center of the circle

· y represents the y coordinate of the center of the circle

· r represents the radius of the circle

Public Methods:

a) The class has two constructors:

o Constructor#1 : a default constructor, Circle() which sets x = 0, y= 0 and r = 0

b) Constructor #2 : a parameter constructor, Circle (int a, int b, int c) which sets x = a, y = b and r = c , where a and , b, and c are specified input values

c) public int getX() : returns the X coordinate of the center of the Circle

d) public int getY() : returns the Y coordinate of the center of the Circle

e) public int getRadius() : returns the radius of the Circle

f) public void setX(int a ) : sets the X coordinate of the center of the Circle to equal the input value, a (specified by the user)

g) public void setY (int b ) : sets the Y coordinate of the center of the Circle to equal the input value, b (specified by the user)

h) public void setR(int c) : sets the radius of the Circle to equal the input value, c (specified by the user)

i) public double getArea() : computes and returns the area of the Circle

j) public int checkQuadrant() : returns 1 if the Circle is inscribed in the first quadrant, 2 for second quadrant, 3 for third quadrant and 4 for the fourth quadrant.

For this problem, you can assume that an input circle will always be inscribed completely within one of the four quadrants. Hence, no input circle will overlap between more than one quadrant.

Program output:

Input x Coordinate

5

Input y Coordinate

5

Input radius

3

The center of the Circle = (5, 5)

Area of the Circle = 28.274

The circle is in Quadrant#1

Changing the center and radius of the Circle:

Input X Coordinate

-8

Input y Coordinate

12

Input radius

4

Area = 50.265

The center of the Circle = (-8, 12)

Area of the Circle = 50.265

The circle is in Quadrant#2

Problem #2:

Write programs to implement the following:

1) Circle.java implements a Circle class as specified above.

2) CircleTestArray.java implements the following:

a. Creates an array (of input size) of type Circle.

b. Creates and stores an instance of the Circle class for every cell in the array

c. Takes integer input values for center of the circle (x and y coordinates) and radius for every Circle object in the array

d. Computes the area for every Circle object in the array

e. Prints the Quadrant# (1 or 2 or 3 or 4) for every Circle object in the array

f. Prints the number of Circle objects in each quadrant (see program output below)

Program output:

How many circles do you want to create?

4

Input x Coordinate for Circle#1

5

Input y Coordinate for Circle#1

5

Input radius for Circle#1

2

Area for Circle#1 = 12.566370614359172

Circle#1 is in Quadrant#1

Input x Coordinate for Circle#2

6

Input y Coordinate for Circle#2

-12

Input radius for Circle#2

3

Area for Circle#2 = 28.274333882308138

Circle#2 is in Quadrant#4

Input x Coordinate for Circle#3

-5

Input y Coordinate for Circle#3

10

Input radius for Circle#3

4

Area for Circle#3 = 50.26548245743669

Circle#3 is in Quadrant#2

Input x Coordinate for Circle#4

-5

Input y Coordinate for Circle#4

6

Input radius for Circle#4

1

Area for Circle#4 = 3.141592653589793

Circle#4 is in Quadrant#2

Number of Circles in Quadrant#1 = 1

Number of Circles in Quadrant#2 = 2

Number of Circles in Quadrant#3 = 0

Number of Circles in Quadrant#4 = 1