CSC 204 Drill and Practice

1. CSC 204 Drill and Practice Creating and Using Classes

2. Constructors • Given a class named Animal, what will its constructor be named?

3. Instance variables • The data stored for an Animal is: • its weight (a floating point number) • its breed (a string) • its age (an integer) • Give instance variables for each of these fields.

4. Constructors • Create a constructor for Animal that takes values for each of the instance variables. • The data stored for an Animal is: • its weight (a floating point number) • its breed (a string) • its age (an integer)

5. Constructors • Show how to call the constructor you just wrote to assign the data for a 5 year old, 16 pound cat to the variable myCat.

6. Constructors • Create a constructor for Animal that uses the default values below for each of the instance variables. • its weight: 10 • its breed: "Unknown" • its age : 1

7. Constructors • Create a constructor for Animal that uses the default values below for each of the instance variables that calls the 3 parameter constructor you have already created. • its weight: 10 • its breed: "Unknown" • its age : 1

8. Constructors • Show how to call the constructor you just wrote to assign data to the variable thatCreature.

9. Accessors • Create a toString method that returns a string with the data for the animal formatted as shown below: • Animal: <breed>, <weight> lbs.,<age> years old • Calling this with myCat should return: • Animal: cat, 16 lbs.,5 years old

10. Accessors • Show how to call toString to print out the information about myCat. • Give another way to call toString to print out the information about thatCritter.

11. Accessors • Create accessors to return all three pieces of instance data of an Animal.

12. Accessors • Show how to call the accessors you just created to print the information about myCat, one piece of data per line.

13. Accessors • Create a compareTo method that will compare two animals based on their weights (so the heavier one is considered "larger").

14. Accessors • Create a compareAge method that will compare two animals based on their ages (so the older one is considered "larger").

15. Accessors • Create a compareBreed method that will compare two animals based on their breeds (so the breed that appears alphabetically later is considered "larger").

16. Accessors • Using the compare methods you just wrote, compare myCat and thatCreature and tell which is heavier.

17. Accessors • Using the compare methods you just wrote, compare myCat and thatCreature and tell which is older.

18. Accessors • Using the compare methods you just wrote, compare myCat and thatCreature and print their breeds in alphabetical order.

19. Accessors • Create an equals method that will return true if two animals have the same age, weight, and breed.

20. Mutators • Create a birthday method that will add one to the age of an Animal.

21. Mutators • Show how to add 1 to the age of myCat and print its age.

22. Class variables • The class Animal needs to keep track of the animals it has created. In particular, it needs to keep track of: • the total number of animals that have been created (an integer) • the total weight of the animals that have been created (a floating point number) • Give class variables for each of these fields.

23. Class variables • Create accessors to return the class variables you just created.

24. Class variables • Show how to print the values of the class variables you just created, using the accessors.

25. Class variables • Show the changes needed to the constructor to update the class variables each time a new animal is created.

26. Mutators • Create a changeWeight method that will add a given amount to the weight of an Animal. • Remember to update the class variable.

27. Class variables and array lists • The class Animal needs to keep track of all the animals it has created. • Give a class variables that will maintain an array list of all animals.

28. Class variables • Show the changes needed to the constructor to update allAnimals each time a new animal is created.

29. Class variables and array lists • Create a method to return a string with all animals that have been created, one per line. • Use toString to get the information for each animal.

30. Class variables and array lists • Show how to print out all the animals that have been created.