Destructors in a Class | C++ Object Oriented Tutorial
Summary
TLDRIn this C++ programming tutorial by Anil, viewers are introduced to destructors, the counterpart to constructors. Destructors are special member functions executed when an object goes out of scope or is deleted, ensuring proper resource cleanup. The tutorial demonstrates creating a 'Human' class with both a constructor and destructor, using the 'new' keyword to create an object and 'delete' to deallocate its memory, illustrating the sequence of constructor and destructor calls. Anil emphasizes the importance of destructors in managing memory and their restrictions, such as no parameters or return values, before concluding with a reminder to subscribe for more educational content.
Takeaways
- 📘 The script is a C++ programming tutorial focused on destructors.
- 🔨 Destructors in C++ are special member functions that execute when an object goes out of scope or is deleted.
- 👉 Destructors are the opposite of constructors, which are called when an object is created.
- 📝 The destructor is declared with the `~` symbol followed by the class name and has no parameters or return values.
- 👷♂️ The tutorial demonstrates creating a class named 'human' with both a constructor and a destructor.
- 💬 The destructor is used to execute statements before the object's memory is released.
- 🔑 The scope resolution operator can be used to define the destructor outside the class.
- 🗑️ Demonstration includes creating an object with the 'new' keyword and deleting it to trigger the destructor.
- 🔄 When an object is created, the constructor is called, and when it's destroyed, the destructor is called.
- 🛠️ The tutorial includes a practical example of creating and deleting an object to illustrate the use of destructors.
- 👋 The presenter encourages viewers to subscribe for more tutorials and ends with a reminder for the next session.
Q & A
What is the purpose of a destructor in C++?
-A destructor in C++ is a special member function of a class that is executed whenever an object of its class goes out of scope or when the delete expression is applied to a pointer to the object. It is used to release the memory allocated for the object and perform any necessary cleanup before the object is destroyed.
How is a destructor different from a constructor in C++?
-A constructor is a special member function that is called when a new object of a class is created, while a destructor is called when an object is about to be destroyed. Unlike constructors, destructors cannot take parameters and cannot return any values.
What symbol is used to declare a destructor in C++?
-The tilde symbol (~) is used to declare a destructor in C++, followed by the class name and a pair of parentheses.
Can a destructor be defined outside the class using the scope resolution operator?
-Yes, a destructor can be defined outside the class using the scope resolution operator, which is the double colon (::).
What happens when an object is created using the 'new' keyword in C++?
-When an object is created using the 'new' keyword in C++, the constructor of the class is called to initialize the object, and memory is allocated for it.
What is the role of the 'delete' keyword in C++?
-The 'delete' keyword in C++ is used to deallocate the memory that was previously allocated for an object using the 'new' keyword. It also calls the destructor of the object.
What is the correct syntax for defining a destructor in a C++ class?
-The correct syntax for defining a destructor in a C++ class is to use the tilde symbol (~), followed by the class name, a pair of parentheses, and then the body of the destructor enclosed in curly braces.
When is the destructor called for an object created within a function scope?
-The destructor for an object created within a function scope is called when the function execution is completed and the object goes out of scope.
Can destructors have parameters or return values?
-No, destructors in C++ cannot have parameters and cannot return any values. They are meant for cleanup and releasing resources.
What is the significance of the 'see out and' statement used in the destructor example?
-The 'see out and' statement in the destructor example is likely a placeholder for a more meaningful action or message that should be executed or displayed when the destructor is called. It serves as a demonstration of where such actions would occur.
How can you observe the effect of a destructor in a C++ program?
-You can observe the effect of a destructor in a C++ program by creating an object, running the program to see the constructor message, then deleting the object or allowing it to go out of scope and observing the destructor message.
Outlines
📚 Introduction to C++ Destructors
Anil introduces a C++ programming tutorial focused on destructors, explaining that they are special member functions executed when an object goes out of scope or is deleted. He contrasts this with constructors, which are called when objects are created. The tutorial aims to demonstrate the use of destructors by building a 'Human' class with both a constructor and a destructor. The destructor is declared with a tilde prefix and the same name as the class, and it cannot take arguments or return values. Anil also mentions the option to define the destructor outside the class using the scope resolution operator.
Mindmap
Keywords
💡Destructors
💡Constructors
💡Class
💡Object
💡Scope
💡Pointer
💡Memory Allocation
💡Delete Expression
💡Tilde Symbol (~)
💡Scope Resolution Operator (::)
💡Video Tutorial
Highlights
Introduction to the concept of destructors in C++ programming.
Relates destructors to constructors, explaining their opposite roles in object lifecycle.
Destructors are special member functions executed when an object goes out of scope or is deleted.
Demonstration of building a class named 'human' with a constructor and destructor.
Syntax explanation for declaring a destructor using the tilde symbol and class name.
Destructors cannot take arguments or return values, unlike constructors.
Option to define the destructor outside the class using the scope resolution operator.
Example of writing statements within the destructor to execute before object destruction.
Illustration of creating an object of the 'human' class using the 'new' keyword.
Observation that the destructor is not called immediately after object creation.
Demonstration of calling the destructor by deallocating memory with the 'delete' keyword.
Explanation of when the destructor is called: after object destruction or when going out of scope.
Clarification that destructors have the same name as the class and cannot return values or take parameters.
Emphasis on the importance of destructors in managing memory allocation and deallocation.
Encouragement for viewers to subscribe for more tutorials on C++ programming.
Closing remarks and anticipation for the next tutorial in the series.
Transcripts
hi this is Anil and welcome to the video
tutorial for the learning lad on C++
programming so in this tutorial we're
going to learn about the destructors in
C++ so I believe that you know all of
you guys have watched my previous
tutorials where you know I have
explained about the constructors in C++
you know a Constructor is a special
member function of a class that is
executed whenever we create new objects
of the class but this Destructor are
opposite to that a Destructor is also a
special member function of a class that
is executed whenever an object of its
class goes out of scope or whenever the
delete expression is applied to your
pointer to the object of that class
which is nothing but when we create an
object The Constructor will be called
and when the memory allocated for that
object will be released at that time the
destructor will be called
so here in this tutorial to demonstrate
the use of destructors we're going to
build a class so it's going to be class
hum and here we're going to write the
access specifier as public and let's
create a
Constructor you know the same name as a
class name and within this Constructor
we're going to specify Constructor
called and just end this line and next
we're going to write a special member
function which is the destructor to
declare a Destructor first we need to
use the til symbol the one which is
present above the tab key in your
keyboard and then the class name same as
the constructors here in this case it's
going to be
human and then a pair of parenthesis and
then a pair of curly braces and between
these curly braces we're going to write
the statements that we want to execute
before releasing all the memory
allocated for object the statements
inside this Destructor will be executed
before destroying the object so here
this Destructor cannot take any
arguments and it cannot return any
values but you know the constructors can
take parameters you know which we have
learned in previous tutorials and also
if you want to Define this Destructor
using the scope resolution operator
outside this class you guys can do that
you know and now we're going to write
the statements and just for the
demonstration purpose we're going to use
the see out and and we're going to say
Destructor
called and let's end this
line all right now we have created a
class with Constructor and destructors
the next thing that we're going to do is
we're going to create an object of this
class and here in this case we're going
to use the second method you know where
we are using the new keyword so first we
need a pointer it's going to be human
and and Then star let's say Anil and
then we're going to create an object
using the new is going to be Anil equal
to new
human and no parameters okay now I'm
going to save this I'm going to build
and run this you guys can see the
Constructor called and you know the
destructor is not called that's because
at this moment also the object is
present in the memory you know which is
not destroyed you know the destructor
will be called when the object is being
destroyed that's why what do we're going
to do is we're going to close this one
and uh we're going to use the delete
keyword to deallocate the memory
allocated for this object so it's going
to be
delete and then the pointer Anil and uh
I'm going to save this I'm going to
build and run this now you guys can see
Constructor called and then the
destructor called okay I spelled it
wrong no problem so what we can say is
you know when we create an object the
Constructor will be called and when we
destroy an object using the delete
keyword or you know when uh the function
that contains the object or where the
object created goes out of scope you
know that object will be destroyed at
that time the destructor will be called
a Destructor is a special member
function which has the same name as the
class name and this Destructor cannot
return any values and also we can't pass
any parameters to the destructor so
thank you for watching guys don't foret
to subscribe and I'll see you in the
next tutorial
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