Classes - Basketball

Object Oriented Programming (OOP) is a programming paradigm that promotes the design of programs by having different objects interacting together to solve a problem. C++ is one of the programming languages that promotes object oriented programming, allowing programmers to create their own classes from scratch or derive them from other existing classes. Other languages that promote OOP are Java, Python, JavaScript and PHP.

In OOP, each object encapsulates within itself certain properties about the entity being modeled. For example, an object that models a point encapsulates the coordinates x and y of the point being represented. Furthermore, each object allows certain actions to be carried out on itself with the methods that the object contains. For example, an object of class point could carry out the action of changing the value of the x coordinate.

When an object class we need to use in our program has not been predefined in a library, we need to declare and implement our own class. To do this, we define classes that contain data with certain properties or attributes, and actions that we want to carry out with this data through the use of methods or member functions. This way, we can organize the information and processes in objects that have the properties and methods of a class. In today's laboratory experience, you will practice defining a class and implementing some of its methods by completing a program that simulates a basketball game between two players, maintaining the score for the game and the global statistics for the two players.

Objectives:

Practice the implementation and declaration of classes in C++.
Implement methods in a class.

Pre-Lab:

Before coming to the laboratory you should have:

Reviewed the concepts related to classes and objects.
Studied the skeleton for the program in main.cpp.
Studied the concepts and instructions for the laboratory session.
Taken the Pre-Lab quiz, available in Moodle.

Classes and Objects in C++

An object is an entity that contains data and procedures to manipulate them. Similar to how each variable has a type of data associated to it, each object has a class associated to it, which describes the properties of the the objects: its data (attributes), and the procedures that can be used to manipulate its data (methods).

It is not necessary to know all of the details about the methods of the object to define and use an object, but you must know how to create it and how to interact with it. The necessary information is available in the class' documentation. Before creating objects of any class, we should familiarize ourselves with its documentation. The documentation indicates, among other things, what entity is trying to be represented in the class, and its interface or methods available to manipulate the objects of the class.

To see an example of a class, take a look at the documentation of the Bird class which can be found in this link.

Classes

A class is a description of the data and processes of an object. The class declaration establishes the attributes that each of the objects of the class will have, and the methods that it can invoke.

If it isn't specified otherwise, the attributes and methods defined in a class will be private. This means that the variables can only be accessed and changed by the methods of the class (constructors, setters, and getters, among others).

The following is the skeleton of the declaration of a class:

  class ClassName
   {
    // Declarations

    private:
      // Declaration of variables or attributes
      // and prototype member functions
      // that are private for this class

      type privateVar
      type nameOfPrivateMemFunc(type of the parameters);

    public:
      // Declarations of attributes
      // and prototypes of method functions
      // that are public for the entire program

      type publicVar;
      type nameOfPublicMemFunc(type of the parameters);
   };

The Game

The skeleton for the program that we provide simulates a basketball game between two players. The program uses OOP and simulates the game by creating an object of class BBPlayer for every player and calling its methods. The object that represents every player contains attributes such as the name of the player and the game statistics, i. e. throws taken and made. During the game, a successful throw into the basket receives two points. The program includes random functions and formulas to determine the player that attempts a throw, if the player scores, and the player that takes the rebound. During the simulated game the score for each player is kept and each player's data is updated. At the end of the game, a table with the statistics is displayed.

The algorithm that simulates the game is the following:

1. initialize the player
2. assign jugadorEnOfensiva randomly
3. while (none has won)
4.   simulate a shot to the basket
5.   if (scored)
6.     update the statistics of the player that shot the basket
7.     if (the score >= 32):
8.        inform that the offense player (jugadorEnOfensiva) won 
9.     else:
10.       exchange offensive player
11.  else:
12.    update statistics of the player that shot the basket
13.    determine who gets the rebound
14.    update the statistics of the player that got the rebound
15.    assign a player in offense (jugadorEnOfensiva)
16. show the players statistics

The `BBPlayer` Class

For this laboratory experience, you will define the BBPlayer class that contains the attributes and methods that are described below. Since some of the functions that are already defined in the provided code use attributes and methods of this class, it is important that you use the same names that we indicate. The commented code in the main function and in test_BBPlayer will help you determine the type of data the method should return, the types the parameters should have, and the order in which they are included in the function declaration.

Attributes

_name: stores the name of the player
_shotsTaken: stores the number of attempted throws during the tournament
_showsMade: stores the number of throws scored during the tournament
_gamesPlayed: stores the number of games played during the tournament
_rebounds: stores the number of rebounds during the tournament
_score: stores the player's score during the game

Methods

default constructor. (method included in main.cpp)
setAll(): method that assigns an initial value to all of the attributes of the object. Notice that this method is invoked at the beginning of main to assign initial values to the array P that is an array of two objects of the BBPlayer class.
name(): method to acquire the name of the player.
shotPercentage(): method to compute the percent of throws scored; is used to determine if the attempted throw is scored by a player. (method included in main.cpp)
reboundsPerGame(): method to compute the average number of rebounds caught by a player; is used to determine if the player successfully catches the rebound. (method included in main.cpp)
shotMade(): method that registers that a shot was scored, that a shot was attempted, and updates the score for the player.
shotMissed(): method that registers an attempted throw (but unsuccessful).
reboundMade(): method that registers that a rebound was caught.
addGame(): method that registers that a game was played.
score(): method to acquire the score of a player.
printStats(): method that displays a player's statistics. (method included in main.cpp)

Consider a definition of a Point class like the following:

What is a correct inline implementation for a function isFirstQ which return true if the point is in the first quadrant? < The correct answer is:
It correctly states the return-type (bool) and correclty uses the objects data members (x and y) inside the conditional expression. The other solutions have several problems:
1. Using xx and yy instead of x and y (xx and yy are just parameters to the constructor, NOT the actual data member names)
2. Forgetting to establish the return type.
3. Using the class name inside to preceed the data member name (e.g. Point.x)

The function members of a class can have zero o more parameters, depending on the external data that is needed by the function to perform its computation. Which of the following methods for the Point class would require 1 or more parameters? A method $distanceToOrigin$ that returns the distance from the point to the origin. A method $distanceToPoint$ that returns the distance between the invoking point and other point. A method $quadrant$ that returns the number (1, 2, 3, or 4) of the quadrant where the point lies. A method $onAxis$ that returns true if the point lies in an axis. To compute the distance of two points, the method $distanceToPoint$ would require information about other point (besides the data of the invoking object). The rest of the methods could be implemented with 0 parameters.
One way to implement $distanceToPoint$ would be:

Laboratory Session:

In this laboratory experience, your task will be to define the BBPlayer class with the attributes and method prototypes listed above. The skeleton for the program includes the code to define some of the methods; others you will have to define.

The skeleton for the program also includes the test_BBPlayer function that does unit tests to each of the functions in the program. The tests are commented and, as you define each function, you will remove the comments, test and modify the function, until the test for that function is passed. Once all of the functions are ready and have passed the tests, the whole program is tested by removing the necessary comments in the main function.

Exercise 1 - Download and understand the provided code

Instructions

Load the project basket01 into QtCreator. There are two ways to do this:
- Using the virtual machine: Double click the file basket01.pro located in the folder /home/eip/labs/classes-basket01 of your virtual machine.
- Downloading the project�s folder from Bitbucket: Use a terminal and write the command git clone http:/bitbucket.org/eip-uprrp/classes-basket01 to download the folder classes-basket01 from Bitbucket. Double click the file basket01.pro located in the folder that you downloaded to your computer.
This program will run on the terminal and you should select this option from the "Projects" window. To access this window, you select "Projects" in the vertical menu to the left. Afterwards, in Build & Run you select Run and then mark the box that says Run in terminal.
Study and understand the code in the main.cpp file, including the code that is commented.

Exercise 2 - Define the `BBPlayer` class

Instructions

Define the BBPlayer class with the specifications included in the section The BBPlayer Class. For each one of the methods that are specified above:
a. Include a prototype for the method in the class definition.
b. If the corresponding member function is already coded in the program, remove the comments from the corresponding sections for this function in test_BBPlayer.
c. If the corresponding member function is not coded, define the function and then remove the comments from the corresponding sections for this function in test_BBPlayer.
d. Run the program and verify that it passed all of the tests. You should obtain a window similar to the one in Figure 1. If your code does not pass all the tests, revise your code. Repeat until your code has passed all of the tests.
Figure 1. Example of the window you should obtain if the code passes the unit tests.
Once you have all of the functions defined and tested, uncomment the code in the main function to test the whole program. If the program functions correctly, you should obtain a window that starts similarly to the one in Figure 2 and finishes like the one in Figure 3.

![figure2.png](images/figure2.png)


**Figure 2.** Example of the start of the window you should obtain if the program functions correctly.

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![figure3.png](images/figure3.png)


**Figure 3.** Example of the window you should obtain at the end of the program if it is working correctly.

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**IMPORTANT:** You SHOULD NOT make any changes in the `main` and `test_BBPlayer` functions, aside from removing the comments.

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Deliverables

Use "Deliverable" in Moodle to hand in the main.cpp file. Remember to use good programming techniques, include the name of the programmers involved, and document your program.

References

[1] http://www.telegraph.co.uk/sport/olympics/basketball/9348826/London-2012-Olympics-Temi-Fagbenle-in-Team-GB-womens-basketball-squad.html

[2] http://www.musthavemenus.com/category/bar-clipart.html

[3] http://basketball.isport.com/basketball-guides/finding-your-niche-in-basketball

classes-basket

Classes - Basketball

Objectives:

Pre-Lab:

Classes and Objects in C++

Classes

The Game

The `BBPlayer` Class

Attributes

Methods

Laboratory Session:

Exercise 1 - Download and understand the provided code

Instructions

Exercise 2 - Define the `BBPlayer` class

Instructions

Deliverables

References

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Classes - Basketball

Objectives:

Pre-Lab:

Classes and Objects in C++

Classes

The Game

The BBPlayer Class

Attributes

Methods

Laboratory Session:

Exercise 1 - Download and understand the provided code

Instructions

Exercise 2 - Define the BBPlayer class

Instructions

Deliverables

References

results matching ""

No results matching ""

The `BBPlayer` Class

Exercise 2 - Define the `BBPlayer` class