### Understanding the Circle Class CodeHere we examine the provided code for a `Circle` class and explore the behavior when invoking a specific statement on an object of this class.```javapublic class Circle { private int radius; private int x; private int y; public Circle(int r) { this.radius = r; } public double getArea() { return Math.PI * radius * radius; } public String toString(int n) { return x + " " + y + " " + radius; } // The rest of the code for the Circle class // .......}```#### Code Breakdown1. **Class Declaration:** - `public class Circle {` (Line 1) declares a new class named `Circle`.2. **Instance Variables:** - `private int radius;` (Line 2) defines a private instance variable `radius`. - `private int x;` (Line 3) defines a private instance variable `x`. - `private int y;` (Line 4) defines a private instance variable `y`.3. **Constructor:** - `public Circle(int r) {` (Line 6) is the constructor that initializes the `radius` variable. - `this.radius = r;` (Line 8) assigns the value `r` to the instance variable `radius`.4. **Method to Calculate Area:** - `public double getArea() {` (Line 11) declares a method to calculate the area of the circle. - `return Math.PI * radius * radius;` (Line 13) returns the calculated area using the formula $ \pi \times \text{radius}^2 $.5. **toString Method:** - `public String toString(int n) {` (Line 17) declares a method that takes an integer parameter `n` (not used in the method) and returns a string. - `return x + " " + y + " " + radius;` (Line 18) returns a string representation of the `x`, `y`, and `radius` values.6. **Placeholder for Additional Code:** - Comments (Lines 21–22) indicate that there may be additional code not shown here.### Problem Statement:Assume that a `Circle

Consider the following code: 1. public class Circle { private int radius; private int x; private int y; 2. 3. 4. 5. 6. public Circle(int r) { 7. 8. this.radius = r; 9. } public double getArea() { 10. 11. 12. 13. return Math.PI * radius *radius; 14. } 15. 16. 17. public String toString(int n) { return x+ " " + y + " " 18. + radius; 19. } 20. // The rest of the code for the Circle class //........ 21. 22. 23. } Assume that a Circle object c is already created with a radius of 12. What is the result of of the following statement: System.out.printIn(c); O A. This is a syntax error O B. 00 12 O C. The address of the Circle object OD. This is a run time error

Consider the following code: 1. public class Circle { private int radius; private int x; private int y; 2. 3. 4. 5. 6. public Circle(int r) { 7. 8. this.radius = r; 9. } public double getArea() { 10. 11. 12. 13. return Math.PI * radius *radius; 14. } 15. 16. 17. public String toString(int n) { return x+ " " + y + " " 18. + radius; 19. } 20. // The rest of the code for the Circle class //........ 21. 22. 23. } Assume that a Circle object c is already created with a radius of 12. What is the result of of the following statement: System.out.printIn(c); O A. This is a syntax error O B. 00 12 O C. The address of the Circle object OD. This is a run time error

Programming Logic & Design Comprehensive

9th Edition

ISBN:9781337669405

Author:FARRELL

Publisher:FARRELL

Chapter10: Object-oriented Programming

Section: Chapter Questions

Problem 16RQ

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A(n) ____________ is one instance or variable of a class.
Using classes, design an online address book to keep track of the names, addresses, phone numbers, and dates of birth of family members, close friends, and certain business associates. Your program should be able to handle a maximum of 500 entries. Define a class addressType that can store a street address, city, state, and ZIP code. Use the appropriate functions to print and store the address. Also, use constructors to automatically initialize the member variables. Define a class extPersonType using the class personType (as defined in Example 10-10, Chapter 10), the class dateType (as designed in this chapters Programming Exercise 2), and the class addressType. Add a member variable to this class to classify the person as a family member, friend, or business associate. Also, add a member variable to store the phone number. Add (or override) the functions to print and store the appropriate information. Use constructors to automatically initialize the member variables. Define the class addressBookType using the previously defined classes. An object of the type addressBookType should be able to process a maximum of 500 entries. The program should perform the following operations: Load the data into the address book from a disk. Sort the address book by last name. Search for a person by last name. Print the address, phone number, and date of birth (if it exists) of a given person. Print the names of the people whose birthdays are in a given month. Print the names of all the people between two last names. Depending on the users request, print the names of all family members, friends, or business associates.
Chapter 10 defined the class circleType to implement the basic properties of a circle. (Add the function print to this class to output the radius, area, and circumference of a circle.) Now every cylinder has a base and height, where the base is a circle. Design a class cylinderType that can capture the properties of a cylinder and perform the usual operations on the cylinder. Derive this class from the class circleType designed in Chapter 10. Some of the operations that can be performed on a cylinder are as follows: calculate and print the volume, calculate and print the surface area, set the height, set the radius of the base, and set the center of the base. Also, write a program to test various operations on a cylinder.
In previous chapters, you have created programs for the Greenville Idol competition. Now create a Contestant class with the following characteristics: The Contestant class contains public static arrays that hold talent codes and descriptions. Recall that the talent categories are Singing Dancing, Musical instrument, and Other. The class contains an auto-implemented property that holds a contestants name. The class contains fields for a talent code and description. The set accessor for the code assigns a code only if it is valid. Otherwise, it assigns I for Invalid. The talent description is a read-only property that is assigned a value when the code is set. Modify the GreenvilleRevenue program so that it uses the Contestant class and performs the following tasks: The program prompts the user for the number of contestants in this years competition; the number must be between 0 and 30. The program continues to prompt the user until a valid value is entered. The expected revenue is calculated and displayed. The revenue is $25 per contestant. The program prompts the user for names and talent codes for each contestant entered. Along with the prompt for a talent code, display a list of the valid categories. After data entry is complete, the program displays the valid talent categories and then continuously prompts the user for talent codes and displays the names of all contestants in the category. Appropriate messages are displayed if the entered code is not a character or a valid code.
Create an application for Ninas Cookie Emporium named CookieDemo that declares and demonstrates objects of the CookieOrder class and its descendants. The CookieOrder class includes auto-implemented properties for an order number, recipients name, and cookie type (for example, chocolate chip), and fields for number of dozens ordered and price. When the field value for number of dozens ordered is set, the price field is set as $15 per dozen for the first two dozen and $13 per dozen for each dozen over two. Create a child class named Special Cookieorder, which includes a field with a description as to why the order is special (for example, gluten-free). Override the method that sets a CookieOrders price as described in part a, but also to include special handling, which is SIO for orders up to $40 and $8 for higher-priced orders. Create an application named CookieDem02 that demonstrates using several Special CookieOrder objects.
a. Write a FractionDemo program that instantiates several Fraction objects and demonstrates that their methods work correctly. Create a Fraction class with fields that hold a whole number, a numerator, and a denominator. In addition: Create properties for each field. The set access or for the denominator should not allow a 0 value; the value defaults to 1. Add three constructors. One takes three parameters for a whole number, numerator, and denominator. Another accepts two parameters for the numerator and denominator; when this constructor is used, the whole number value is 0. The last constructor is parameterless; it sets the whole number and numerator to 0 and the denominator to 1. (After construction, Fractions do not have to be reduced to proper form. For example, even though 3/9 could be reduced to 1/3, your constructors do not have to perform this task.) Add a Reduce() method that reduces a Fraction if it is in improper form. For example, 2/4 should be reduced to 1/2. Add an operator+() method that adds two Fractions. To add two fractions, first eliminate any whole number part of the value. For example, 2 1/4 becomes 9/4 and 1 3/5 becomes 8/5. Find a common denominator and convert the fractions to it. For example, when adding 9/4 and 8/5, you can convert them to 45/20 and 32/20. Then you can add the numerators, giving 77/20. Finally, call the Reduce() method to reduce the result, restoring any whole number value so the fractional part of the number is less than 1. For example, 77/20 becomes 3 17/20. Include a function that returns a string that contains a Fraction in the usual display formatâ€”the whole number, a space, the numerator, a slash (D, and a denominator. When the whole number is 0, just the Fraction part of the value should be displayed (for example, 1/2 instead of 0 1/2). If the numerator is 0, just the whole number should be displayed (for example, 2 instead of 2 0/3). b. Add an operator*() method to the Fraction class created in Exercise 11a so that it correctly multiplies two Fractions. The result should be in proper, reduced format. Demonstrate that the method works correctly in a program named FractionDemo2. c. Write a program named FractionDem03 that includes an array of four Fractions. Prompt the user for values for each. Display every possible combination of addition results and every possible combination of multiplication results for each Fraction pair (that is, each type will have 16 results).
Write a program named SalespersonDemo that instantiates objects using classes named Real EstateSalesperson and GirlScout. Demonstrate that each object can use a SalesSpeech() method appropriately. Also, use a MakeSale() method two or three times with each object, and display the final contents of each objects data fields. First, create an abstract class named Salesperson. Fields include first and last names; the Salesperson constructor requires both these values. Include properties for the fields. Include a method that returns a string that holds the Salespersons full nameâ€”the first and last names separated by a space. Then perform the following Create two child classes of Salesperson: Real EstateSalesperson and Girl Scout. The Real EstateSalesperson class contains fields for total value sold in dollars and total commission earned (both of which are initialized to 0), and a commission rate field required by the class constructor. The Girl Scout class includes a field to hold the number of boxes of cookies sold, which is initialized to 0. Include properties for every field. Create an interface named ISell able that contains two methods: SalesSpeech() and MakeSale(). In each Real EstateSalesperson and Girl Scout class, implement SalesSpeech() to display an appropriate one- or two-sentence sales speech that the objects of the class could use. In the Real Estatesalesperson class, implement the MakeSale() method to accept an integer dollar value for a house, add the value to the Real EstateSalespersons total value sold, and compute the total commission earned. In the Girl Scout class, implement the MakeSale() method to accept an integer representing the number of boxes of cookies sold and add it to the total field.