What is a Class and Object in C++?

Question

What is a Class and Object in C++?

Can we say that a Class is an Object?

Answer 1

When you define a class, you define a blueprint for a data type. This doesn't actually define any data, but it does define what the class name means, that is, what an object of the class will consist of and what operations can be performed on such an object.

A class definition starts with the keyword class followed by the class name; and the class body, enclosed by a pair of curly braces. A class definition must be followed either by a semicolon or a list of declarations. For example, we defined the Box data type using the keyword class as follows:

class Box
{
   public:
      double length;   // Length of a box
      double breadth;  // Breadth of a box
      double height;   // Height of a box
};

The keyword public determines the access attributes of the members of the class that follow it. A public member can be accessed from outside the class anywhere within the scope of the class object. You can also specify the members of a class as private or protected which we will discuss in a sub-section.

Answer 2

Here is an anology.
we have a classification called vehicles. Each vehicle will have some properties like :

• seating capacity
• fuel capacity
• fuel consumption
• type of transmission

Car, bike, truck, are some instances of vehicles. Each may have different set of properties.
Here vehicles is a class and all the properties are it's members and car, bike, truck are objects of the class vehicles.

Answer 3

Class is a collection of data member and member function.

Class is a user define data type.

Object is a class type variable.

Objects are also called instance of the class.

Each object contains all members(variables and functions) declared in the class. We can access any data member or member function from object of that class using . operator.

Answer 4

In C++, Objects are essentially the variables and Classes are the types of their values.

Answer 5

No, an object is an instance of a class...

Unless...

If you are implementing a software design tool that allows you to represent classes, interfaces, properties, inheritance, associations, aggregations, etc., then at runtime, yes, each class you place in the designer will be an object instance of the Class class. Ok, couldn't help myself finding an example so twisted and meta.

Now seriously, a class is not an object.

Answer 6

Object is an data or a function which has an adress in run time memory and are also called as instances of class . Thus object is an class type variable or entity of c++ programming language.