A constructor is a special member function that initializes objects of a class. Constructors are automatically called when an object is created. There are different types of constructors like the default constructor, parameterized constructor, copy constructor, and dynamic constructor. A destructor is used to destroy objects and is called automatically when an object goes out of scope.

2. A constructor is a member function of a class which
initializes objects of a class. In C++, Constructor is
automatically called when object(instance of class)
create. It is special member function of the class.

3.  Constructor has same name as the class itself
 Constructors don’t have return type
 A constructor is automatically called when an object
is created.
 If we do not specify a constructor, C++ compiler
generates a default constructor for us (expects no
parameters and has an empty body).

4.  We can not refer to their addresses.
 An object with a constructor (or destructor) can not
be used as a member of a union.
 They make ‘implicit calls’ to the operators new and
delete when memory allocation is required.

5.  Default Constructor
 Parameterizes Constructor
 Copy Constructor
 Dynamic Constructor

6.  Default constructor is the constructor which doesn’t take any argument.
 It has no parameters.
 The default constructor for class A is A : : A ( )
Note: Even if we do not define any constructor explicitly, the compiler
will automatically provide a default constructor implicitly.

8.  They should be declared in the public section.
 They are invoked automatically when the objects
are created.
 They do not have return types, not even void and
they cannot return values.

9.  It may be necessary to initialize the various data
elements of different objects with different
values when they are created.
 This is achieved by passing arguments to the
constructor function when the objects are
created.
 The constructors that can take arguments are
called parameterized constructors.

12.  When an object is declared in a parameterized
constructor, the initial values have to be passed as
arguments to the constructor function.
 The normal way of object declaration may not work.
 The constructors can be called explicitly or
implicitly.

13.  It is used to initialize the various data elements of
different objects with different values when they are
created.
 It is used to overload constructors.

14.  In C++, We can have more than one constructor in
a class with same name, as long as each has a
different list of arguments. This concept is known
as Constructor Overloading and is quite similar
to Function Overloading.

15.  Overloaded constructors essentially have the same
name (name of the class) and different number of
arguments.
 A constructor is called depending upon the number
and type of arguments passed.
 While creating the object, arguments must be
passed to let compiler know, which constructor
needs to be called.

18. A copy constructor is a member function which
initializes an object using another object of the
same class. A copy constructor has the following
general function prototype:
ClassName (const ClassName &old_obj);

19.  A reference variable has been used as an
argument to the copy constructor.
 We cannot pass the argument by value to a copy
constructor.
continue …

20. A copy constructor is called when an object is passed by value.
Copy constructor itself is a function. So if we pass an argument
by value in a copy constructor, a call to copy constructor
would be made to call copy constructor which becomes a non-
terminating chain of calls. Therefore compiler doesn’t allow
parameters to be passed by value.

21. One reason for passing const reference is, we should use const
in C++ wherever possible so that objects are not accidentally
modified. This is one good reason for passing reference as
const

24. In C++, a Copy Constructor may be called in following cases:
 When an object of the class is returned by value.
 When an object of the class is passed (to a function) by value
as an argument.
 When an object is constructed based on another object of the
same class.
 When the compiler generates a temporary object.

25. When allocation of memory is done dynamically using
dynamic memory allocator new in a Constructor, it is known
as dynamic constructor. By using this, we can dynamically
initialize the objects.

26.  Allocation of memory to objects at the time of
their construction is known as dynamic
construction of objects.
 The memory is created with the help of the new
operator.

28. A destructor is used to destroy the objects that have been
created by a constructor.
OR
Destructor is a member function which destructs or deletes
an object.

29. A destructor function is called automatically when the object
goes out of scope:
(1) the function ends
(2) the program ends
(3) a block containing local variables ends
(4) a delete operator is called

30.  A destructor never takes any argument nor does it return any
value.
 It will be invoked implicitly by the compiler upon exit from
the program – or block or function as the case may be – to
clean up storage that is no longer accessible.
 Destructors have same name as the class preceded by a tilde
(~)
 There cannot be more than one destructor in a class.

31.  They do not have any return type, just like constructors.
 When you do not specify any destructor in a class, compiler
generates a default destructor and inserts it into your code.
 Unlike constructors that can have parameters, destructors do
not allow any parameter.

32. ~class_name()
{
//Some code
}

35. THANK YOU