OOP stands for Object-Oriented Programming.
Procedural programming is about writing procedures or functions that perform operations on the data, while object-oriented programming is about creating objects that contain both data and functions.
Object-oriented programming has several advantages over procedural programming:
Note: The "Don't Repeat Yourself" (DRY) principle is about reducing the repetition of code. You should extract out the codes that are common for the application, and place them at a single place and reuse them instead of repeating it.
Classes and objects are the two main aspects of object-oriented programming.
Look at the following illustration to see the difference between class and objects:
So, a class is a template for objects, and an object is an instance of a class.
When the individual objects are created, they inherit all the variables and functions from the class.
C++ is an object-oriented programming language.
Everything in C++ is associated with classes and objects, along with its attributes and methods. For example: in real life, a car is an object. The car has attributes, such as weight and color, and methods, such as drive and brake.
Attributes and methods are basically variables and functions that belongs to the class. These are often referred to as "class members".
A class is a user-defined data type that we can use in our program, and it works as an object constructor, or a "blueprint" for creating objects.
To create a class, use the class keyword:
Example
Create a class called "MyClass":
class MyClass { // The class
public: // Access specifier
int myNum; // Attribute (int variable)
string myString; // Attribute (string variable)
};
Example explained
In C++, an object is created from a class. We have already created the class named MyClass, so now we can use this to create objects.
To create an object of MyClass, specify the class name, followed by the object name.
To access the class attributes (myNum and myString), use the dot syntax (.) on the object:
Example
Create an object called "myObj" and access the attributes:
class MyClass { // The class
public: // Access specifier
int myNum; // Attribute (int variable)
string myString; // Attribute (string variable)
};
int main() {
MyClass myObj; // Create an object of MyClass
// Access attributes and set values
myObj.myNum = 15;
myObj.myString = "Some text";
// Print attribute values
cout << myObj.myNum << "\n";
cout << myObj.myString;
return 0;
}
You can create multiple objects of one class:
Example
// Create a Car class with some attributes
class Car {
public:
string brand;
string model;
int year;
};
int main() {
// Create an object of Car
Car carObj1;
carObj1.brand = "BMW";
carObj1.model = "X5";
carObj1.year = 1999;
// Create another object of Car
Car carObj2;
carObj2.brand = "Ford";
carObj2.model = "Mustang";
carObj2.year = 1969;
// Print attribute values
cout << carObj1.brand << " " << carObj1.model << " " << carObj1.year << "\n";
cout << carObj2.brand << " " << carObj2.model << " " << carObj2.year << "\n";
return 0;
}
15 videos|20 docs|13 tests
|
|
Explore Courses for Class 10 exam
|