Classes & Objects

Class

Class is a logical entity contains the information of their members like member method, member variable, static method, static variable, access modifier, constructor, destructor & constant.

the class keyword is used to define a class.

• Class is a user-defined data type.

• Class members are by default private.

• Whichever is written inside a class, called members of the class

Syntax

Example

#include <iostream>
using namespace std;

class Student {
    public:
    string studentName;

    void walk() {
        cout << "walking..." << endl;
    } 
};

class Student {
    public:
    string studentName;

    void walk() {
        cout << "walking..." << endl;
    }
}

Explanation

In the above example, Student is the name of the class, and public is an access modifier (access specifier), studentName is a variable (properties of student), walk is a method.

• studentName and walk both are members of Student class.

Object

An object is a real-world entity, which is declared at compile time and initialize at runtime.

• An object is a collection member variable.

• An object is stored in the heap area.
• We create any number of objects of a class.

Syntax of creating an object

ClassName object1;

Example

#include <iostream>
using namespace std;

class Student {
    public:
    string studentName;

    void walk() {
        cout << "walking..." << endl;
    } 
};

int main(int argc, char const *argv[]) {
    Student s1; // s1 is an object of Student class

    // give name to student
    s1.studentName = "Online Vidyalay";

    // calling method
    s1.walk();

    return 0;
}

// output
// walking...