Lecture 6 Constructor and DestructorOOP1: Video (ith attribuits.GameCinitelf.nanelf.heaf.levshowint(fclass MyClass:def_init__(self, name):self.name = nameprint(f'{self.name} created")def _del_(self):print(f'{self.name} destroyed")# Creating objects and adding multiple referencesa = MyClass("Object A"b=a #b points to the#Deleting one referenceoutputdel a # destructor will not be called because b still points to the object#Deleting all referencesdel b # Now there are no references to the object, so destructor will be calledcatveliarwhar

Correct Code class MyClass: # Constructor def __init__(self, name): self.name = name…

Answered: Lecture 6 Constructor and Destructor…

Microsoft Visual C#

7th Edition

ISBN:9781337102100

Author:Joyce, Farrell.

Publisher:Joyce, Farrell.

Chapter9: Using Classes And Objects

Section: Chapter Questions

Problem 19RQ

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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).
In Chapter 9, you created a Contestant class for the Greenville Idol competition. The class includes a contestants name, talent code, and talent description. The competition has become so popular that separate contests with differing entry fees have been established for children, teenagers, and adults. Modify the Contestant class to contain a field that holds the entry fee for each category, and add get and set accessors. Extend the Contestant class to create three subclasses: ChildContestant, TeenContestant, and AdultContestant. Child contestants are 12 years old and younger, and their entry fee is $15. Teen contestants are between 13 and 17 years old, inclusive, and their entry fee is S20. Adult contestants are 18 years old and older, and their entry fee is $30. In each subclass, set the entry fee field to the correct value, and override the Tostring() method to return a string that includes all the contestant data, including the age category and the entry fee. Modify the GreenvilleRevenue program so that it performs the following tasks: The program prompts the user for the number of contestants in this years competition, which must be between 0 and 30. The program continues to prompt the user until a valid value is entered. The program prompts the user for names, ages, and talent codes for the contestants entered. Along with the prompt for a talent code, display a list of valid categories. Based on the age entered for each contestant, create an object of the correct type (adult, teen, or child), and store it in an array of Contestant objects. After data entry is complete, display the total expected revenue, which is the sum of the entry fees for the contestants. After data entry is complete, display the valid talent categories and then continuously prompt the user for talent codes, and display all the data for all the contestants in each category. Display an appropriate message if the entered code is not a character or a valid code.
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.
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.
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.
The implementation of a queue in an array, as given in this chapter, uses the variable count to determine whether the queue is empty or full. You can also use the variable count to return the number of elements in the queue. On the other hand, class linkedQueueType does not use such a variable to keep track of the number of elements in the queue. Redefine the class linkedQueueType by adding the variable count to keep track of the number of elements in the queue. Modify the definitions of the functions addQueue and deleteQueue as necessary. Add the function queueCount to return the number of elements in the queue. Also, write a program to test various operations of the class you defined.

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