Assignment 3: Inheritance

Transcription

1 Assignment 3: Inheritance Due Wednesday March 21 st, 2012 by 11:59 pm. Submit deliverables via CourSys: Late penalty is 10% per calendar day (each 0 to 24 hour period past due). March 23 rd is the last possible day to submit (11:59 pm). This assignment must be done individually. Do not show other students your code, do not copy code found online, and do not post questions about the assignment online. Please direct all questions to the instructor or TA: cmpt-212-help@sfu.ca; See the marking guide for details on how each part will be marked. 1. NumberList Implement a class named NumberList which can store integers and perform some basic functions on them such as sum, min and max. The complete class is shown in the UML below. 1.1 Implement NumberList Implement all methods shown in the diagram. Here are some specific notes: Name your files numberlist.h and numberlist.cpp. Public inheritance makes all the member functions of QList<int> available in the public interface of NumberList. Implement a copy constructor, a copy assignment operator, and a default constructor. For each, you will basically be calling the base class. Do not rely on the ones provided by the compiler; implement each manually. The integer conversion constructor creates a NumberList containing a single element. Make this constructor explicit so you Figure 1: NumberList UML class diagram. cannot do the following: NumberList list; list = 1; // Should give compiler error. Your code must match perfectly the UML diagram: we will be testing each of the functions listed here. You may add additional member variables and member functions as needed. Match the member function names, parameters, return types, and visibility. Be careful to match the pass-by-reference, pass-by-pointer, and default parameters. Generated Mar 9, 2012, 11:34 PM Page 1/6 Dr. Fraser

2 Set the bool (which is passed-by-pointer to min(), max() and average()) to false when there is no data in the NumberList. This indicates that the return value is not valid. Otherwise set it to true. When the list is empty, these functions return 0. tostring() behaves similar to the QStringList's join functionality. For example, tostring() on {2, 3, 4} with delimiter -> becomes 2->3->4. Ensure you do not add a trailing delimiter. Be sure to handle positive and negative numbers correctly. Your class must be const-correct. The UML diagram does not show which are const member functions. Make any function which does not need to change the NumberList be const. Iterator note: In const-functions, you will need a const iterator, such as: for (QList<int>::const_iterator itr = mylist.constbegin(); itr!= mylist.constend(); itr++) { cout << *itr; } Code 1: Constant iterator using the C++ STD style. Note also that the class you are working in is-a QList<int>. So, you can directly access const_iterator, constbegin(), constend() and so on. You must use all three types of iterators in your code. 1.2 Test code for NumberList Implement code to test your NumberList class. Use Q_ASSERT()'s to check conditions. For example: NumberList list; list << 1 << 2; Q_ASSERT(list.toString() == "1, 2"); Q_ASSERT(list.toString(":") == "1:2"); Code 2: Use of Q_ASSERT() to check code. Your code must reasonably test each public function you have written. Each of the class's public functions you wrote must be called at least once. Demonstrate that most of these functions work with empty lists, positive and negative numbers, short lists and longer lists. Your class will be tested using a suite of tests, plus your test code will be marked. Generated Mar 9, 2012, 11:34 PM Page 2/6 Dr. Fraser

3 2. Shapes In this part you will implement a system for drawing basic shapes using characters on the terminal. A Canvas class is provided to handle the basic drawing. The shape classes use an inheritance hierarchy to build up functionality without repeating code. The classes are shown in the following detailed UML diagram; each class is described below. Figure 2: Shape class hierarchy. Generated Mar 9, 2012, 11:34 PM Page 3/6 Dr. Fraser

4 2.1 Understanding the Canvas The Canvas class is provided on the course website. Use it to draw to the screen Canvas UML (right) Sample Code & UML void democanvas() { // Create the screen with a default // background (fill): Canvas screen('.'); // Put a T top left, a B bottom right: screen.setpoint(0, 0, 'T'); screen.setpoint(canvas::size_x - 1, Canvas::SIZE_Y - 1, 'B'); // Draw two lines: horizontal '*'s, and diagonal '\\'s for (int i = 0; i < 10; i++) { screen.setpoint(i, 2, '*'); screen.setpoint(i + 10, i + 10, '\\'); } } // Actually show it to the screen: screen.show(); Sample Output T... **********......\......\......\......\......\......\......\......\......\......\......B Generated Mar 9, 2012, 11:34 PM Page 4/6 Dr. Fraser

5 2.2 Shape Implement a class named Shape, as shown in Figure 1. Some notes on this class: Store the top-left X and Y coordinates of the shape (integers) as private member variables. The constructor sets the coordinates and initializes the style (see next point) to the defaults. Any derived classes needing to access the coordinates must use the accessor functions. The fill and border characters are used by derived classes when drawing to the screen. All Shapes are drawn with a border (the border character), and are filled in (the fill character). Provide accessor member functions for all private data. Create a virtual destructor. Create a pure virtual draw() function which accepts a reference to a Canvas object. Each derived class will override draw() to draw itself to the Canvas. Each class inheriting from Shape will draw itself as a filled-solid with a border. 2.3 Triangle The Triangle draws a right-triangle where the left and base (bottom) are the same size. See sample output. The Triangle's size cannot be less than 1. X and Y of the Shape class are the top left corner of the Triangle. 2.4 Rectangle The Rectangle stores a width and height, each must be no less than length 1. X and Y of the Shape class are the top left corner of the Rectangle. 2.5 TextBox The TextBox is-a Rectangle and adds a message inside it. When drawn on a Canvas, the TextBox places the text inside the box drawn by the Rectangle. Do not repeat the drawing code from Rectangle! You wrote it once; it works; use it! Rendering the text is non-trivial: If the message is too long to fit on one line, it must be split across multiple lines. Be careful to skip the spaces that you break the lines on. If there is a space on the line, break on the space; otherwise fill the entire line inside the Rectangle with text and break mid-word. Each line of text must be centred horizontally inside the Rectangle. If there are an odd number of extra spaces on the line, it does not matter if the extra space is before or after the text, or even if it is inconsistent. For example: Extra space after: " Hi " Extra space before: " Hi " Text need not be centred vertically; start output on the first line inside the Rectangle. Text must not overlap the Rectangle's border (drawn by Rectangle::draw()). 2.6 Picture The Picture class holds a list of Shapes and can draw them to the screen via a Canvas. add() accepts a pointer to a Shape and stores it in the list. When draw() is called it iterates through all the Shapes and calls each draw() function. Its destructor frees all memory for the stored Shapes. Generated Mar 9, 2012, 11:34 PM Page 5/6 Dr. Fraser

6 2.7 General Points See the test code posted on the course website for a sample usage of these classes. You must be able to run this without modification. Your code must be const correct. Note the UML diagram does not indicate which methods are const. Your code must use correct naming conventions, as described in the style guide. You may add additional member variables and member functions to any of the classes except the Canvas; however, your code must support at least all the methods found in the UML diagram above. See posted files online for sample output. 3. Testing You will be submitting all your.h and.cpp files. The TA will be using the following sequence of commands to build your system. You should ensure that your code will build. 1. Copy.h and.cpp files into a new folder names as2 on the CSIL Linux machines in SUR Copy the provided test files into the same folder. 3. Build a Qt project file (.pro): > qmake -project 4. Create a project makefile: > qmake 5. Build the project: > make 6. Run your program; it should not take any input from either the command line or the user. >./as2 NOTE: Double check the case of all filenames (lower case) and the case of all includes (also lower case)! These seem not to cause problems in the lab, but do on other systems. 4. Deliverables Submit two zip files to CourSys ( ): NumberList.zip: containing just your.h and.cpp files for the NumberList, along with its test code. Shapes.zip: containing just your.h and.cpp files for the shapes part, including main.cpp. Note that the case of the ZIP file name matters! Each of your.cpp and.h files must begin with a comment stating your name, your SFU user ID, and your SFU student number. Please remember that all submissions will be compared for unexplainable similarities. 5. Change History None (yet!). Generated Mar 9, 2012, 11:34 PM Page 6/6 Dr. Fraser