CSE143 Inheritance Example            

Assuming that the following classes have been defined:

        public class MusicPlayer {
            public void method1() {
                System.out.println("MusicPlayer1");
            }
        }
                                    
        public class TapeDeck extends MusicPlayer {
            public void method3() {
                System.out.println("TapeDeck3");
            }
        }
        
        public class IPod extends MusicPlayer {
            public void method2() {
                System.out.println("IPod2");
                method1();
            }
        }
        
        public class IPhone extends IPod {
            public void method1() {
                System.out.println("IPhone1");
                super.method1();
            }
        
            public void method3() {
                System.out.println("IPhone3");
            }
        }
        
And assuming the following variables have been defined:

            MusicPlayer var1 = new TapeDeck();
            MusicPlayer var2 = new IPod();
            MusicPlayer var3 = new IPhone();
            IPod var4 = new IPhone();
            Object var5 = new IPod();
            Object var6 = new MusicPlayer();

In the table below, indicate in the right-hand column the output produced by
the statement in the left-hand column.  If the statement produces more than one
line of output, indicate the line breaks with slashes as in "a/b/c" to indicate
three lines of output with "a" followed by "b" followed by "c".  If the
statement causes an error, fill in the right-hand column with either the phrase
"compiler error" or "runtime error" to indicate when the error would be
detected.

        Statement                             Output
        ------------------------------------------------------------------

        var1.method1();                       ____________________________
      
        var2.method1();                       ____________________________
      
        var3.method1();                       ____________________________
      
        var4.method1();                       ____________________________
      
        var5.method1();                       ____________________________
      
        var6.method1();                       ____________________________
      
        var4.method2();                       ____________________________
      
        var4.method3();                       ____________________________

        ((TapeDeck) var1).method2();          ____________________________

        ((IPod) var1).method2();              ____________________________

        ((TapeDeck) var1).method3();          ____________________________

        ((IPhone) var2).method1();            ____________________________
   
        ((IPhone) var3).method1();            ____________________________
   
        ((IPhone) var4).method3();            ____________________________

        ((MusicPlayer) var5).method1();       ____________________________
        
        ((IPod) var3).method2();              ____________________________

        ((IPhone) var5).method2();            ____________________________

        ((IPod) var5).method2();              ____________________________

        ((MusicPlayer) var6).method1();       ____________________________

        ((MusicPlayer) var6).method2();       ____________________________

        ((TapeDeck) var6).method3();          ____________________________

                    
                    Solution to CSE143 Inheritance Example

        Statement                               Output
        --------------------------------------------------
        var1.method1();                         MusicPlayer1
        var2.method1();                         MusicPlayer1
        var3.method1();                         IPhone1/MusicPlayer1
        var4.method1();                         IPhone1/MusicPlayer1
        var5.method1();                         compiler error
        var6.method1();                         compiler error
        var4.method2();                         IPod2/IPhone1/MusicPlayer1
        var4.method3();                         compiler error
        ((TapeDeck) var1).method2();            compiler error
        ((IPod) var1).method2();                runtime error
        ((TapeDeck) var1).method3();            TapeDeck3
        ((IPhone) var2).method1();              runtime error
        ((IPhone) var3).method1();              IPhone1/MusicPlayer1
        ((IPhone) var4).method3();              IPhone3
        ((MusicPlayer) var5).method1();         MusicPlayer1
        ((IPod) var3).method2();                IPod2/IPhone1/MusicPlayer1
        ((IPhone) var5).method2();              runtime error
        ((IPod) var5).method2();                IPod2/MusicPlayer1
        ((MusicPlayer) var6).method1();         MusicPlayer1
        ((MusicPlayer) var6).method2();         compiler error
        ((TapeDeck) var6).method3();            runtime error