(TFI) Run For Leprosy 2015

Kusta adalah penyakit yang disebabkan oleh Mycobacterium leprae yang menyerang kulit, saraf tepi, jaringan dan organ tubuh lain (kecuali otak) dan menimbulkan kecacatan. Meskipun tergolong ke dalam penyakit menular, kusta merupakan penyakit yang tidak mudah menular, karena diperlukan kontak erat secara terus menerus dan dalam waktu yang lama dengan penderita. Penyakit kusta sebenarnya dapat disembuhkan tanpa cacat bila penderita ditemukan dan diobati secara dini. Kenyataannya, penyakit kusta seringkali ditemukan terlambat dan sudah dalam keadaan cacat yang terlihat. Pada dasarnya, terdapat 2 tingkatan kecacatan penyakit kusta saat ditemukan, yaitu tingkat I dan II. Kecacatan tingkat I adalah cacat yang belum terlihat atau belum ada perubahan pada anatominya. Sementara kecacatan tingkat II adalah sudah terjadi perubahan yang nampak pada anatomi penderita kusta. Maka dari itu perlu diketahui gejala-gejala awal munculnya penyakit kusta:

1. Lesi (kelainan) kulit yang mati rasa
Kelainan kulit/ lesi dapat berbentuk bercak keputih – putihan (hypopigmentasi) atau kemerah merahan (erithematous) yang mati rasa (anesthesi)

2. Penebalan Saraf Tepi
Biasanya disertai dengan gangguan fungsi saraf. Gangguan fungsi saraf ini merupakan akibat dari peradangan kronis saraf tepi (neuritis perifer). Gangguan fungsi saraf ini bisa berupa :
Gangguan fungsi sensori : mati rasa
Gangguan fungsi motoris : kelemaha otot (parese) atau kelumpuhan (paralise)
Gangguan fungsi Otonom : Kulit kering dan retak – retak

3. Adanya bakteri tahan asam (BTA) di dalam kerokan jaringan kulit (BTA Positif)

Tanda – tanda pada kulit:
1. Bercak/ kelainan kulit yang merah atau putih di bagian tubuh
2. Bercak yang tidak gatal dan kulit mengkilap
3. Adanya bagian tubuh yang tidak berkeringat atau tidak berambut
4. Lepuh tidak nyeri
5. Tanda-tanda pada saraf
6. Rasa kesemutan, tertusuk-tusuk dan nyeri pada anggota badan
7. Gangguan gerak anggota badan atau bagian muka
8. Adanya cacat (deformitas) dan luka (ulkus) yang tidak mau sembuh

Seperti yang telah disebutkan bahwa penyakit kusta adalah penyakit yang dapat disembuhkan. Akan tetapi banyak penderita kusta yang terlambat mendapatkan penanganan dan pengobatan. Hal ini dikarenakan adanya syndrome leprophobia dimana masyarakat merasa jijik dan menyeramkan melihat tubuh dari penderita kusta, bahkan terkadang masyarakat mengalami ketakutan yang berlebihan terhadap penderita kusta.
Melihat masih minimnya pengetahuan masyarakat akan penyakit kusta maka diperlukan sosialisasi kepada masyarakat seperti dimulai dengan mengadakan seminar yang bertemakan bagaimana cara hidup sehat, kemudian menjelaskan kepada masyarakat penyebab dan ciri-ciri gejala kusta sehingga dengan berbekal pengetahuan tentang kusta, masyarakat dapat tanggap dalam memberikan pertolongan pertama kepada penderita kusta. Dan juga diharapkan dengan adanya sosialisasi dapat menghilangkan stigma-stigma negatif yang melekat pada masyarakat mengenai penyakit kusta.

Oleh karna itu, TFI (Teach For Indonesia) Binus University mengadakan acara Run For Leprosy untuk memperingati world leprosy day 2015 yang diadakan pada tanggal 15 maret 2015 dalam kategori 5k dan 10k. Acara ini diikuti kurang lebih hampir 3500 peserta.

Saya sebagai salah satu pelari merasa senang karena acara ini selain dapat menyehatkan tubuh juga dapat membantu teman-teman kita yang sedang menderita penyakit kusta. Selain itu juga acara ini menunjukkan kepada masyarakat bahwa penderita kusta bukanlah sesuatu yang harus ditakuti dan dikucilkan, melainkan mereka merupakan orang-orang yang membutuhkan bantuan kita. Saya juga berkomitmen untuk tidak memandang teman-teman yang menderita penyakit kusta sebagai seseorang yang dikucilkan atau dijauhi melainkan sebagai seseorang yang butuh bantuan dan pertolongan dari kita sebagai sesama manusia.

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Chapter 16; Logic Programming Languages; 779-781

review question

1. What are the three primary uses of symbolic logic in formal logic?
– Express propositions
– Express relationships between propositions
– Describe how new propositions can be inferred from other propositions

2. What are the two parts of a compound term?
– Functor: function symbol that names the relationship
– Ordered list of parameters (tuple)

3. What are the two modes in which a proposition can be stated?
Fact and query

4. What is the general form of a proposition in clausal form?
B1 u B2 u … u Bn c A1 n A2 n … n Am
means if all the As are true, then at least one B is true

5. What are antecedents? Consequents?
Antecedents are right side of a clausal form proposition. Consequent is left side of a clausal form propositions

6. Give general definitions of resolution and unification
– Resolution : inference rule that allows inferred propositions to be computed from given propositions, thus providing a method with potential application to automatic theorem proving.
– Unification : Process of determining useful values for variables.

7. What are the forms of Horn clauses?
Headed and headless.

9. What does it mean for a language to be nonprocedural?
Programs do not state now a result is to be computed, but rather the form of the result

Problem Set

2. Describe how a multiple-processor machine could be used to implement resolution. Could Prolog, as currently defined, use this method?
On a single processor machine, the resolution process takes place on the rule base, one rule at a time, starting with the first rule, and progressing toward the last until a match is found.  Because the process on each rule is independent of the process on the other rules, separate processors could concurrently operate on separate rules.  When any of the processors finds a match, all resolution processing could terminate.

9. From a book on Prolog, learn and write a description of a monkey-banana prolem. Why does Prolog allow this problem to exist in its implementation ?
– The problem is defined as this : a monkey is in a room. Suspended from the ceiling is a bunch of bananas, beyond the monkey’s reach. However, in the room there are also a chair and a stick. The ceiling is just the right height so that a monkey standing on a chair could knock the bananas down with the stick. The monkey knows how to move around, carry other things around, reach for the bananas, and wave a stick in the air. What is the best sequence of actions for the monkey?
It exists to create a variation in output of Prolog. As Prolog is an AI programming language, a variation might be needed in AI output to make them respond relevant to the situation.

10.  Using the internet for reference, find some of the applications of expert systems.

• Expert system in healthcare: The Electronic health record (EHR) is designed to replace the traditional medical and bring together a more versatile, expansive and robust expert system to provide greater quality care.

• Expert systems in the financial field: Loan departments are interested in expert systems for morgages because of the growing cost of labour, which makes the handling and acceptance of relatively small loans less profitable.

• A new application for expert systems is automated computer program generation. Funded by a US Air Force grant, an expert system-based application (hprcARCHITECT) that generates computer programs for mixed processor technology (FPGA/GPU/Multicore) systems without a need for technical specialists has recently been commercially introduced

Chapter 15; Functional Programming Languages; 741-744

Review questions

2. What does a lambda expression specify?
The predicate function is often given as a lambda expression, which in ML is defined exactly like a function, except with the fn reserved word, instead of fun, and of course the lambda expression is nameless.

5. Explain why QUOTE is needed for a parameter that is a data list.
To avoid evaluating a parameter, it is first given as a parameter to the primitive function QUOTE, which simply returns it without change.

6. What is a simple list?
A list which membership of a given atom in a given list that does not include sublists.

7. What does the abbreviation REPL stand for?
REPL stand for read-evaluate-print loop.

11. What are the two forms of DEFINE?
The simplest form of DEFINE is one used to bind a name to the value of an expression. This form is
(DEFINE symbol expression)
The general form of such a DEFINE is
(DEFINE (function_name parameters)
(expression)
)

13. Why are CAR and CDR so named?
The names of the CAR and CDR functions are peculiar at best. The origin of these names lies in the first implementation of LISP, which was on an IBM 704 computer. The 704’s memory words had two fields, named decrement and address, that were used in various operand addressing strategies. Each of
these fields could store a machine memory address. The 704 also included two machine instructions, also named CAR (contents of the address part of a register) and CDR (contents of the decrement part of a register), that extracted the associated fields. It was natural to use the two fields to store the two pointers
of a list node so that a memory word could neatly store a node. Using these conventions, the CAR and CDR instructions of the 704 provided efficient list selectors. The names carried over into the primitives of all dialects of LISP.

18. What is tail recursion? Why is it important to define functions that use recursion to specify repetition to be tail recursive?
A function is tail recursive if its recursive call is the last operation in the function. This means that the return value of the recursive call is the return value of the nonrecursive call to the function. It is important to specify repetition to be tail recursive because it is more efficient(increase the efficiency).

19. Why were imperative features added to most dialects of LISP?
LISP began as a pure functional language but soon acquired some important imperative features to increased its execution efficiency.

26. What is type inferencing, as used in ML?
Type inference refers to the automatic deduction of the type of an expression in a programming language. If some, but not all, type annotations are already present it is referred to as type reconstruction.

29. What is a curried function?
Curried functions a function which a new functions can be constructed from them by partial evaluation.

30. What does partial evaluation mean?
Partial evaluation means that the function is evaluated with actual parameters for one or more of the leftmost formal parameters.

32. What is the use of the evaluation environment table?
A table called the evaluation environment stores the names of all implicitly and explicitly declared identifiers in a program, along with their types. This is like a run-time symbol table.

33. Explain the process of currying.
The process of currying replaces a function with more than one parameter with a function with one parameter that returns a function that takes the other parameters of the initial function.

Problem Set

2.  Give the general form of function declaration in ML.

Function declarations in ML appear in the general form
fun function_name( formal parameters ) = expression;

9. What does the following Scheme function do?
(define (y s lis)
(cond
((null? lis) ‘() )
((equal? s (car lis)) lis)
(else (y s (cdr lis)))
))
y returns the given list with leading elements removed up to but not including the first occurrence of the first given parameter.

10. What does the following Scheme function do?
(define (x lis)
(cond
((null? lis) 0)
((not (list? (car lis)))
(cond
((eq? (car lis) #f) (x (cdr lis)))
(else (+ 1 (x (cdr lis))))))
(else (+ (x (car lis)) (x (cdr lis))))
x returns the number of non-NIL atoms in the given list.

Chapter 14; Exception Handling and Event Handling; 685-688

Review Question

1. Define exception, exception handler, raising an exception, disabling an exception, continuation, finalization, and built-in exception.
– Exception : any unusual event, erroneous or not, that is detectable by either hardware or software and that may require special processing.
– Exception handler : a code unit which processes an exception.
– Raising an exception : When a event associated with an exception occurs
– Disabling an exception : Ignoring a certain hardware-detectable exceptions.
– Continuation : Control transfer to somewhere in the program outside of the handler code or program might terminate .
– Finalization : ability to complete some computation regardless of how subprogram execution terminates.
– Built-in exception : Exception that is not made by the user, but rather comes as default.

3. What are the advantages of having support for exception handling built in to a language?
Error detection code is tedious to write and it clutters the program. Exception handling encourages programmers to consider many different possible errors. Exception propagation allows a high level of reuse of exception handling code

4. What are the design issues for exception handling?
How are user-defined exceptions specified?
Should there be default exception handlers for programs that do not provide their own?
Can built-in exceptions be explicitly raised?
Are hardware-detectable errors treated as exceptions that can be handled?
Are there any built-in exceptions?
How can exceptions be disabled, if at all?
How and where are exception handlers specified and what is their scope?
How is an exception occurrence bound to an exception handler?
Can information about the exception be passed to the handler?
Where does execution continue, if at all, after an exception handler completes its execution? (continuation vs. resumption)
Is some form of finalization provided?

5. What does it mean for an exception to be bound to an exception handler?
A specific exception is to be handled by a specific exception handler also, because different exceptions are to be treated differently.

6. What are the possible frames for exceptions in Ada?
The frame of an exception handler in Ada is either a subprogram body, a package body, a task, or a block

7. Where are unhandled exceptions propagated in Ada if raised in a subprogram? A block? A package body? A task?
If the block or unit in which an exception is raised does not have a handler for that exception, the exception is propagated elsewhere to be handled
Procedures – propagate it to the caller
Blocks – propagate it to the scope in which it appears
Package body – propagate it to the declaration part of the unit that declared the package (if it is a library unit, the program is terminated)
Task – no propagation; if it has a handler, execute it; in either case, mark it “completed”

8. Where does execution continue after an exception is handled in Ada?
Control simply continues after the exception clause.

10. What are the four exceptions defined in the Standard package of Ada?
Constraint_Error, Program_Error, Storage_Error, and Tasking_Error.

Problem Set

1.What mechanism did early programming languages provide to detect or attempt to deal with errors?

Early programming languages were designed and implemented in such a way that the user program could neither detect nor attempt to deal with such errors. In these languages, the occurrence of such an error simply causes the program to be terminated and control to be transferred to the operating system.

2.Describe the approach for the detection of subscript range errors used in C and Java.

In C subscript ranges are not checked. Java compilers usually generate code to check the correctness of every subscript expression. If any exception generates, then an unchecked exception is thrown.

6.In languages without exception-handling facilities, it is common to have most subprograms include an “error” parameter, which can be set to some values representing “OK” or some other value representing “error in procedure”. What advantage does a linguistic exception-handling facility like that of Ada have over this method?

There are several advantages of a linguistic mechanism for handling exceptions, such as that found in Ada, over simply using a flag error parameter in all subprograms. One advantage is that the code to test the flag after every call is eliminated. Such testing makes programs longer and harder to read. Another advantage is that exceptions can be propagated farther than one level of control in a uniform and implicit way. Finally, there is the advantage that all programs use a uniform method for dealing with unusual circumstances, leading to enhanced readability.
7.In languages without exception-handling facilities, we could send an error-handling procedure as parameter to each procedure that can detect errors than must be handled. What disadvantage are there to this method?

There are several disadvantages of sending error handling subprograms to other subprograms. One is that it may be necessary to send several error handlers to some subprograms, greatly complicating both the writing and execution of calls. Another is that there is no method of propagating exceptions, meaning that they must all be handled locally. This complicates exception handling, because it requires more attention to handling in more places.

14. Summarize the arguments in favor of the termination and resumption models of continuation.

The resumption model is useful when the exception is only an unusual condition, rather than an error. The termination model is useful when the exception is an error and it is highly unlikely that the error can be corrected so that execution could continue in some
useful way.

Chapter 13; Concurrency; 645-648

review Questions

1. What are the three possible levels of concurrency in programs?
Instruction level, Statement level, and Unit level

2. Describe the logical architecture of an SIMD computer.
Computers that have multiple processors that execute the same instruction simultaneously

3. Describe the logical architecture of an MIMD computer.
Computers that have multiple processors that operate independently but whose operations can be synchronized

4. What level of program concurrency is best supported by SIMD computers?
Instruction concurrency level

5. What level of program concurrency is best supported by MIMD computers?
Unit concurrency level.

6. Describe the logical architecture of a vector processor.
Vector processors have groups of registers that store the operands of a vector operation in which the same instruction is executed on the whole group of operands simultaneously

7. What is the difference between physical and logical concurrency?
Physical concurrency – Multiple independent processors (multiple threads of control)
Logical concurrency – The appearance of physical concurrency is presented by time-sharing one processor (software can be designed as if there were multiple threads of control)

8. What is a thread of control in a program?
A thread of control in a program is the sequence of program points reached as control flows through the program

12. What is a heavyweight task? What is a lightweight task?
Heavyweight tasks execute in their own address space. Lightweight tasks all run in the same address space – more efficient

Problem Set

1. Explain clearly why a race condition can create problems for a system.

Race condition can create problems for a system, because two or more tasks are racing to use the shared resource and the behavior of the program depends on which task arrives first (and wins the race).

2.   The different ways to handle deadlock:

– Ignoring deadlock

– Detection

– Prevention

– Avoidance

3.    Busy waiting is a method whereby a task waits for a given event by continuously checking for that event to occur. What is the main problem with this approach?

Busy-waiting or spinning is a technique in which a process repeatedly checks to see if a condition is true, such as whether keyboard input or a lock is available. Spinning can also be used to generate an arbitrary time delay, a technique that was necessary on systems that lacked a method of waiting a specific length of time. Processor speeds vary greatly from computer to computer, especially as some processors are designed to dynamically adjust speed based on external factors, such as the load on the operating system. Busy waiting may loop forever and it may cause a computer freezing.

Chapter 12; Support for Object-Oriented Programming; 590- 591

Review Questions

1.Name two functional languages that support object-oriented programming

C++, C#, Ada 95

10. What is inner class?

nonstatic classes that are nested directly in another class

12. From where are smalltalk object allocated?

from the heap and are referenced through reference variables, which are implicitly dereferenced

14. What type checking is done in Smalltalk? when does it take place?

the only type checking in smalltalk is dynamic. when a message is sent to an object that has no matching method, either locally or through inheritance

15. What kind of inheritance, single or multiple does smalltalk support?

smalltalk support single inheritance, it does not allow multiple inheritance

16.what are the two most important effects that smalltalk has had on computing?

The integrated use of windows, mouse pointing devices, and pop up and pull down menus.

19.How are c++ heap-allocated objects deallocated?

using delete

23.What are the differences between private and public derivations in C++?

Private members are accessible only by member functions and friends of the class. Public members are visible everywhere

25.What are mixins in objective-C?

mixins are sometimes used to add certain functionaliities to different classes

29.Does Objective-C support multiple inheritance?

Objective C only support single inheritance

31.What are the root class in objective C?

NSobject

37.From where can Java object be allocated?

All java objects are explicit heap dynamic. most are allocated with the new operator, but there is no explicit deallocation operator

38.what is boxing?

convert primitive value to an object of the wrapper class of the primitive value’s type.

40.Are all java subclasses subtype?

subclasses should be subtype

45.are all ada 95 subclasses subtype?

subclasses that are nit subtypes

48.how are getter method defined in a ruby class?

attr_reader: one,: two

51.are all ruby subclasses subtype?

subclass obviously cannot be a subtype

Problem Set

2. In what ways can “compatible “ be defined for the relationship between an overridden method and the overriding method?

Every overriding method must have the same number of parameters as the overridden method and the types of the parameters and the return type must be compatible with those of the parent class.

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.

• The meaning of protected member access specifier is somewhat different in Java. In Java, protected members of a class “A” are accessible in other class “B” of same package, even if B doesn’t inherit from A (they both have to be in the same package).

• Java uses extends keyword for inheritence. Unlike C++, Java doesn’t provide an inheritance specifier like public, protected or private. Therefore, we cannot change the protection level of members of base class in Java, if some data member is public or protected in base class then it remains public or protected in derived class. Like C++, private members of base class are not accessible in derived class. Unlike C++, in Java, we don’t have to remember those rules of inheritance which are combination of base class access specifier and inheritance specifier.

5. Compare abstract class and interface in Java.

• First and major difference between abstract class and interface is that, abstract class is a class while interface is a interface, means by extending abstract class you can not extend another class because Java does not support multiple inheritance but you can implement multiple inheritance in Java.
• Second difference between interface and abstract class in Java is that you can not create non abstract method in interface, every method in interface is by default abstract, but you can create non abstract method in abstract class. Even a class which doesn’t contain any abstract method can be abstract by using abstract keyword.
• Third difference between abstract class and interface in Java is that abstract class are slightly faster than interface because interface involves a search before calling any overridden method in Java. This is not a significant difference in most of cases but if you are writing a time critical application than you may not want to leave any stone unturned.
• Fourth difference between abstract class vs interface in Java is that, interface are better suited for Type declaration and abstract class is more suited for code reuse and evolution perspective.
• Another notable difference between interface and abstract class is that when you add a new method in existing interface it breaks all its implementation and you need to provide an implementation in all clients which is not good. By using abstract class you can provide default implementation in super class.

7. What is one programming situation where multiple inheritance has a significant disadvantage over interfaces?

A situation when there are two classes derived from a common parent and those two derived class has one child.

9. Give an example of inheritance in C++, where a subclass overrides the superclass methods.

class Enemy{

protected:

int Hp;

public:

void attack(){

cout<<”Enemy Attacks using GUN!!”<<endl;
}
};

class BossEnemy: public Enemy{

public:

void attack(){

cout<<”Boss Enemy attacks using MAGIC!!”<<endl;
}
};

10. Explain one advantage of inheritance.

One of the key benefits of inheritance is to minimize the amount of duplicate code in an application by sharing common code amongst several subclasses. Where equivalent code exists in two related classes, the hierarchy can usually be refactored to move the common code up to a mutual superclass. This also tends to result in a better organization of code and smaller, simpler compilation units.

17. What are the different options for object destruction in Java?

There is no explicit deallocation operator. A finalize method is implicitly called when the garbage collector is about to reclaim the storage occupied by the object.

Chapter 11; Abstract Data Types and Encapsulation Constructs; 539-541

Review Questions

1. What are the two kinds of abstractions in programming language?

Two kinds of abstractions in programming language is process abstraction and data abstraction.

2. Define abstract data type.

Data type that satisfies the following conditions:

  • The representation of objects of the type is hidden from the program units that use the type, so the only direct operations possible on those objects are those provided in the type’s definition.
  • The declarations of the type and the protocols of the operations on objects of the type, which provide the type’s interface, are contained in a single syntactic unit. The type’s interface does not depend on the representation of the objects or the implementation of the operations. Also, other program units are allowed to create variables of the defined type.

9. What is in an Ada package specification? What about a body package?

An Ada package specification has interface of the encapsulation and even more. Meanwhile, body package has implementation of most, if not all, of the entities naemd in the associated package specification.

10. What is the use of the Ada with clause?

It makes the names defined in external packages visible.

11. What is the use of the Ada use clause?

It eliminates the need for explicit qualification of the references to entities from the named package.

12. What is the fundamental difference between a C++ class and an Ada package?

C++ class must be accessed from an instance of itself, whereas Ada packages can be accessed directly.

13. From where are C++ objects allocated?

C++ objects are allocated from the heap.

15. What is the purpose of C++ destructor?

It serves as a deallocator for C++object from the heap, while functionally, destructor serves a debugging aid, in which case they simply display or print the values of some or all object’s data members before those members are deallocated.

16. What are the legal return types of a destructor?

Destructors neither have return types nor use return statements.

22. What is the use of @private and @public derivatives?

They are used to specify the access levels of the instance variables in a class definition. Similar to the reserved words private and public in C++.

23. When are constructors implicitly called in Objective-C?

Constructors in Objective-C are implicitly called after the object is created through the calling of alloc.

26. Why does Java not have destructors?

Because Java has an implicit garbage collection which stores all objects which was supposed to be destroyed.

27. Where are all Java methods defined?

They are all defined completely in a class.

37. What is the name of all Ruby constructors?

Constructors in Ruby are named as initialize.

43. What is a C++ namespace, and what is its purpose?

A namespace is a container for a set of identifiers and allows the disambiguation of homonym identifiers residing in different namespaces. The purpose is to help programs manage the problem of global namespace.

45. Describe a .NET assembly.

.NET assembly is a .NET applications appearing as single dynamic link library (.dll files) or executable files (.exe). An assembly defines a module, which can be separately developed and include several components.

Problem Set

2. Suppose someone designed a stack abstract data type in which the function top returned an access path (or pointer ) rather than returning a copy of the top element. This is not a true data abstraction. Why ? Give an example that illustrates the problem.

– The problem with this is that the user is given access to the stack through the returned value of the “top” function. For example, if p is a pointer to objects of the type stored in the stack, we could have:

p = top(stack1);

*p = 42;

These statements access the stack directly, which violates the principle of a data abstraction.

4.   The advantages of the nonpointer concept in Java?

• There is no memory leak such as dangling pointers or unnamed variables.

• Memory access via pointer arithmetic – this is fundamentally unsafe. Java has a robust security model and disallows pointer arithmetic for this reason.

• Array access via pointer offsets – Java does this via indexed array access so you don’t need pointers. A big advantage of Java’s indexed array access is that it detects and disallows out of bounds array access, which can be a major source of bugs.

• References to objects – Java has this, it just doesn’t call them pointers. Any normal object reference works as one of these.

8.   Some drawbacks of user-defined generic classes in Java 5.0 are: for one thing, they cannot store primitives. Second, the elements cannot be indexed. Elements must be added to user-defined generic collections with the add method.

9.   If the constuctor is absent in Java and C++, it will be automatically made by the compiler.

11.  Destructors in C# are rarely used because it uses garbage collection for most of its heap objects.

12.  Classes in Ruby are dynamic in the sense that members can be added at any time. This is done by simply including additional class definitions that specify the new members.