Class and Objcet

 

class and object:

class:

• 1.       a class is a way to bind data and associated function together.
• 2.       it allows data and function to hidden if necessary for external use.
• 3.       defining a class means creating a user defined data type that behaves as built in data.
• 4.       once a class has been declared we can create any number of object belonging to that class.

syntax:

class class_name

{

private:

data member;

member function;

public:

data member;

member function;

};          //end of class

 

Generally data are placed in private section and function are placed in public section.

• 5.       class contains both data and function . Data are called data member and function are called member function.
• 6.       data and function are defined in private section are not accessible out of the class.
• 7.       data and function placed in public section are only accessible from outside the class.
• 8.       the word private is optional . the data in function of class by default private.

Object:

An object is an instance of a class.

For example, the Car class defines the model, brand, and mileage. Now, based on the definition, we can create objects like

Car suv;
Car sedan;
Car van;

Here, suv, sedan, and van are objects of the Car class. Hence, the basic syntax for creating objects is:

Class_Name object_name;

---

Example 1: Class and Objects in C++

#include <iostream>

using namespace std;

class Car {

  public:

    // class data

    string brand, model;

    int mileage = 0;

    // class function to drive the car

    void drive(int distance) {

        mileage += distance;

    }

    

    // class function to print variables

    void show_data() {

        cout << "Brand: " << brand << endl;

        cout << "Model: " << model << endl;

        cout << "Distance driven: " << mileage << " miles" << endl;

    }

};

int main() {

    

    // create an object of Car class

    Car my_car;

    // initialize variables of my_car

    my_car.brand = "Honda";

    my_car.model = "Accord";

    my_car.drive(50);

    // display object variables

    my_car.show_data();

    return 0; 

}