{"id":792,"date":"2014-10-12T23:26:48","date_gmt":"2014-10-12T12:26:48","guid":{"rendered":"http:\/\/blogs.unsw.edu.au\/comp1400\/?p=792"},"modified":"2014-10-16T18:38:57","modified_gmt":"2014-10-16T07:38:57","slug":"week-11-lab-inheritance","status":"publish","type":"post","link":"https:\/\/blogs.unsw.edu.au\/comp1400\/blog\/2014\/10\/week-11-lab-inheritance\/","title":{"rendered":"Week 11 Lab – Inheritance"},"content":{"rendered":"

The self-test quiz for this week is here<\/a>.<\/p>\n

The following exercises are taken from chapter 8 of the textbook.<\/p>\n

Exercise 8.4<\/strong> Open the\u00a0project dome-v2<\/a>. This project contains a version of the DoME application rewritten to use inheritance, as described above. Note that the classdiagram<\/strong> displays the inheritance relationship. Open the source code of the DVD class and remove the ‘extends Item<\/strong>‘ phrase. Close the editor. What changes do you observe in the class diagram? Add the ‘extends Item<\/strong>‘ phrase again.<\/p>\n

 <\/p>\n

Exercise 8.5<\/strong> Create a\u00a0CD<\/strong> object. Call some of its methods. Can you call the inherited methods (for example,\u00a0setComment<\/strong>)? What do you observe about the inherited methods?<\/p>\n

 <\/p>\n

Exercise 8.6<\/strong> In order to illustrate that a subclass can access non-private elements of the superclass without any special syntax, try the following slightly artificial modification to the\u00a0CD<\/strong> and\u00a0Item<\/strong> classes. Create a method called\u00a0printShortDetails<\/strong>in the\u00a0CD<\/strong>class. Its task is to print just the artist and the title of a CD on a line by itself. However, because the\u00a0titIe<\/strong> field is private in the\u00a0Item<\/strong> class, it will be necessary to add a public\u00a0getTitIe<\/strong> method to Item. Call this method from\u00a0printShortDetails<\/strong> to access the title for printing. Remember that no special syntax is required when a subclass calls a superclass method. Try out your solution by creating a\u00a0CD<\/strong> object. Implement a similar method in the\u00a0DVD<\/strong> class to print just the director and title.<\/p>\n

 <\/p>\n

Exercise 8.8 <\/strong>Open the\u00a0dome-v2 <\/em>project. Add a class for games and a subclass for video games to the project. Create some video game objects and test that all methods work as expected.<\/p>\n

\"Database<\/a><\/p>\n

 <\/p>\n

Exercise 8.12 <\/strong>Assume we have four classes:\u00a0Person<\/strong>,\u00a0Teacher<\/strong>,\u00a0Student<\/strong> andPhDStudent<\/strong>.\u00a0Teacher<\/strong> and\u00a0Student<\/strong> are both subclasses of\u00a0Person<\/strong>.\u00a0PhDStudent<\/strong> is a subclass of\u00a0Student<\/strong>.<\/p>\n

a. Which of the following assignments are legal, and why or why not?
\n
\nPerson p1 = new Student();
\nPerson p2 = new PhDStudent();
\nPhDStudent phd1 = new Student();
\nTeacher t1 = new Person();
\nStudent s1 = new PhDStudent();
\n<\/code><\/p>\n

b. Suppose that we have the following legal declarations and assignments<\/p>\n

Person p1 = new Person();
\nPerson p2= new PerSon ();
\nPhDStudent phd1 = new PhDStudent();
\nTeacher t1 = new Teacher () ;
\nStudent s1 = new Student();
\n<\/code><\/p>\n

Based on those just mentioned, which of the following assignments are legal and or why not?<\/p>\n

s1 = p1;
\ns1\u00a0 = p2;
\np1 = s1;
\nt1 = st;
\ns1 = phd1;
\nphd1 = s1;
\n<\/code><\/p>\n

 <\/p>\n

Exercise 8.13 <\/strong>Test your answers to the previous question by creating bare-bones versions of the classes mentioned in that exercise and trying it out in BlueJ<\/p>\n

 <\/p>\n","protected":false},"excerpt":{"rendered":"

The self-test quiz for this week is here. The following exercises are taken from chapter 8 of the textbook. Exercise 8.4 Open the\u00a0project dome-v2. This project contains a version of the DoME application rewritten to use inheritance, as described above. Note that the classdiagram displays the inheritance relationship. Open the source code of the DVD […]<\/p>\n","protected":false},"author":328,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[630],"tags":[],"class_list":["post-792","post","type-post","status-publish","format-standard","hentry","category-lab"],"_links":{"self":[{"href":"https:\/\/blogs.unsw.edu.au\/comp1400\/wp-json\/wp\/v2\/posts\/792","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blogs.unsw.edu.au\/comp1400\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blogs.unsw.edu.au\/comp1400\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blogs.unsw.edu.au\/comp1400\/wp-json\/wp\/v2\/users\/328"}],"replies":[{"embeddable":true,"href":"https:\/\/blogs.unsw.edu.au\/comp1400\/wp-json\/wp\/v2\/comments?post=792"}],"version-history":[{"count":2,"href":"https:\/\/blogs.unsw.edu.au\/comp1400\/wp-json\/wp\/v2\/posts\/792\/revisions"}],"predecessor-version":[{"id":795,"href":"https:\/\/blogs.unsw.edu.au\/comp1400\/wp-json\/wp\/v2\/posts\/792\/revisions\/795"}],"wp:attachment":[{"href":"https:\/\/blogs.unsw.edu.au\/comp1400\/wp-json\/wp\/v2\/media?parent=792"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.unsw.edu.au\/comp1400\/wp-json\/wp\/v2\/categories?post=792"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blogs.unsw.edu.au\/comp1400\/wp-json\/wp\/v2\/tags?post=792"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}