Question Details

hi am fred. help me to know how to create objects in c++ or java

asked : 1 year, 6 days ago Computer Programming

Answers
Visitor 1544597952 posted an answer
11 months, 23 days ago

C++ Classes and Objects
Class: The building block of C++ that leads to Object Oriented programming is a Class. It is a user defined data type, which holds its own data members and member functions, which can be accessed and used by creating an instance of that class. A class is like a blueprint for an object.
For Example: Consider the Class of Cars. There may be many cars with different names and brand but all of them will share some common properties like all of them will have 4 wheels, Speed Limit, Mileage range etc. So here, Car is the class and wheels, speed limits, mileage are their properties.

A Class is a user defined data-type which has data members and member functions.
Data members are the data variables and member functions are the functions used to manipulate these variables and together these data members and member functions defines the properties and behavior of the objects in a Class.
In the above example of class Car, the data member will be speed limit, mileage etc and member functions can be apply brakes, increase speed etc.
An Object is an instance of a Class. When a class is defined, no memory is allocated but when it is instantiated (i.e. an object is created) memory is allocated.

Declaring Objects: When a class is defined, only the specification for the object is defined; no memory or storage is allocated. To use the data and access functions defined in the class, you need to create objects.

Syntax:

ClassName ObjectName;
Accessing data members and member functions: The data members and member functions of class can be accessed using the dot(‘.’) operator with the object. For example if the name of object is obj and you want to access the member function with the name printName() then you will have to write obj.printName() .

Accessing Data Members

The public data members are also accessed in the same way given however the private data members are not allowed to be accessed directly by the object. Accessing a data member depends solely on the access control of that data member.
This access control is given by Access modifiers in C++. There are three access modifiers : public, private and protected.

// C++ program to demonstrate
// accessing of data members

#include
using namespace std;
class Geeks
{
// Access specifier
public:

// Data Members
string geekname;

// Member Functions()
void printname()
{
cout << "Geekname is: " << geekname;
}
};

int main() {

// Declare an object of class geeks
Geeks obj1;

// accessing data member
obj1.geekname = "Abhi";

// accessing member function
obj1.printname();
return 0;
}
Visitor 1544598066 posted an answer
11 months, 23 days ago

Post Your Own Answer