KBP Chapter 12

This assignment is ordered by Mr. Tri Djoko Wahjono

 

Review question

2. What are the problems associated with programming using abstract data types?

-In nearly all cases, the features and capabilities of the existing type are not quite right for the new use.

-The type definitions are all independent and are at the same level.

4. What is message protocol?

Message protocol is the entire collection of methods of an object.

5. What is an overriding method?

Overriding method is method that overrides the inherited method.

7. What is dynamic dispatch?

Dynamic dispatch is the third characteristic (after abstract data types and inheritance) of object-oriented programming language which is a kind of polymorhphism provided by the dynamic binding of messages to method definitions.

8. What is an abstract method ? What is an abstract class ?
– a method which all descendant classes should have. An abstract class is a class which has abstract method.

10. What is an inner class ?
– Non-static classes that are nested directly in another class

11. What is the message protocol of an object ?
– Colletions of an object’s methods.

12. From where are Smalltalk objects allocated ?
– From the heap

38. What is Boxing ?
– Coercion of primitive values when they are put in object context

52. Does Ruby support multiple inheritance ?
– No. it does not

 

Problem Set

2. In what ways can “compatible “ be defined for the relationship between an overridden method and the overriding method ?
– in ways of its formal definition, the parameters and return types.

3. Compare the inheritance of C++ and Java.
– In Java, all objects are Inherited, either directly or indirectly. While in C++ a class can be defined to stand on its own without an ancestor.

– In Java, there’s no access level specifier of inheritance, while C++ has private public and protected.

– In Java, the functions are virtual by default. While in C++ the functions CAN BE MADE virtual with the keyword virtual

7. What is one programming situation where multiple inheritance has a significant disadvantage over interfaces ?
– When two or more parent classes are derived from one grandparent class and has one child. (diamond problem)

9. Given an example of inheritance in C++, where a subclass overrides the superclass methods.
– class human{
public :
void eat(){std::cout<<”Eating”;}
}
class man : public human{
public :
void eat(){std::cout<<”Eat like a boss”;}
}

10. Explain one advantage of inheritance
– Allows programmer to reuse a class with modifications that doesn’t apply to the initial class, so both class can still be used. This also improves readability and writability.

14. Explain type checking in Java
-Type checking happens before execution. Type checking can only uses type information that have declared in your program, and not the possible type that an object has at runtime. Java checks all line of code to make sure that it uses values correctly according to the declared types.

16. State why Java is said to be more pure object oriented than C++.
-Because Java implements pure class. Every function / statements in Java is run by a class. While in C++ not all functions are run by a class.

17. What are the different options for object destruction in Java ?
– Using Close method or Finalize method.