Question

1. "Shape.java"

You will be given a main() method inside the Shape class. You are going to construct 2 other
classes to make the given main() run successfully.
a. Construct a new class named as "triangle" to store information of some right
triangle shapes. This class contains three parameters: double height, double
base, String color
i. Make two constructors for this class. One only initializes the object with a
String indicating this shape’s color. Another one initializes all three
attributes (height, base, color) for the new object. Check the offered
main() to order the parameters for the constructors.
ii. Write the accessors and mutators methods for these three attributes.
iii. Write a method area() to calculate the triangle’s area by:
T = ℎℎ ∗ /2
This public method receives no parameters (using the class attributes)
and return a double.
b. Construct a new class named as "circle" to store information of some circle
shapes. This class contains three parameters: double radius, String color, final
static double PI = 3.14
i. Make two constructors for this class. One only initializes the object with a
String indicating this shape’s color. Another one initializes radius and
color for the new object. Check the offered main() to order the
parameters for the constructors.

ii. Write the accessors and mutators methods for these two non-constant
attributes.
iii. Write a method area() to calculate the circle’s area by:
c = P ∗ ∗
This public method receives no parameters (using the class attributes)
and return a double.
c. These two new classes should be created in the same file together with the only
public class "Shape". There’s a Shape.java file offered on Canvas, with a finished
main method. You can simply download it and write your "triangle" and "circle"
classes inside that same file. Your running result should be the same as the
following sample running.
d. Please remember to follow the data hiding rules!


Sample Running:
The first triangle's color is red
The area of first triangle is 50.0
The second triangle's information is blue 6.0 3.5
The second triangle is the same color as the first circle
The second circle is green. Its area is 12.56

Generic Grading Guidelines
a. Please make sure you’re only using the concepts already discussed in class. That
is, please try and restrict yourself to loops, selection statements, String methods
that talked on class, arrays, and your own written methods.
b. The programs are worth 50 points each
c. You do not need to perform any form of input type checks.
d. Please make sure you meet the specific requirements, eg. Create the specific
methods/classes, follow data hiding rules.
e. Please make sure that you’re conforming to specifications (program name, print
statements, expected inputs and outputs etc.).
f. Please make sure your code is readable.
g. Please make sure you’ve compiled and run your program before you turn it in. -5
pts will be deducted for each compile error.

Answer 1

The student is tasked with creating two classes within 'Shape.java' to represent a triangle and a circle, each with their specific constructors, accessors, mutators, and area calculation methods, while maintaining data privacy and readability of the code.

Step-by-step explanation:

The question is asking to create two classes, triangle and circle, within a file named Shape.java. These classes are meant to represent geometric shapes with certain properties. Detailed instructions are given on how to construct these classes, including specifying constructors, accessors, mutators, and methods for calculating the areas of these shapes while following the principle of data hiding.

For a triangle, the area calculation is performed using the formula T = (height * base) / 2. The circle class requires a method to calculate the area using the formula C = PI * radius * radius, with PI defined as a constant within the class.

Following object-oriented programming principles and encapsulation, the classes must have private fields to store their attributes, and public methods to interact with these attributes. Readable code and adherence to already discussed concepts in the classroom are essential for successfully completing this assignment.