Classes and Objects in C++: Differences Explained

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In summary, an object is a specific thing and a class is a kind or type of thing. A class is like a template for creating objects with the same properties. In programming, an object is instantiated from a class, meaning it is created based on the class's parameters. Multiple objects can be created from the same class. In simpler terms, a class is a definition while an object is an instance of that definition.
  • #1
torquerotates
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In C++ what is the difference between an object and a class? I'm confused, is an object always a class?
 
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  • #2
An object is what is instantiated from a class.
A class is defined once in a program. From this class, an object can be created (instantiated) from the class, according to the parameters specified. The object so created is an instance of the class. Hence it is possible to instantiate multiple object from the same class.

Here's an example:
// following is the class definition
class Cars
{
char *name;
public:
double price;
Cars(char *n, double p){name=n;price=p;}
};
int main(int argc, char *argv[])
{
// following are pointers to objects, or instances of the class Cars
Cars *Lambourghini=new Cars("Lambourghini", 300000.0);
Cars *Civic=new Cars("Civic", 35000.0);
return 0;
}
 
  • #3
An object is a specific thing. A class is a kind (or type or category) of thing.

Another way of looking at it is to say that a class is a template or "cookie cutter" for creating things (objects) that have the same set of properties.
 
  • #4
It's the same as if you say "int i". "int" is the type and i is a variable of that type.

If I define a class "myClass" and then say "myClass x", "myClass" is the class and "x", a variable of that type, is the object.
 
  • #5
Object is every person like "you" "me" and "HallsofIvy"...
Class is a definition say: Physicsforumer
 
  • #6
If you are familiar with PHP, this tutorial explains how objects are instantiated from a class; it gives a good feel about what role objects play. The tutorial is light-hearted.

http://devzone.zend.com/node/view/id/638
 
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  • #7
A class is a cookie cutter. An object is a cookie.
 

Related to Classes and Objects in C++: Differences Explained

1. What is the difference between a class and an object in C++?

In C++, a class is a blueprint or template for creating objects, while an object is an instance of a class. A class defines the properties and behaviors of objects, while objects are concrete entities that can be created and manipulated in a program.

2. How do classes and objects relate to each other in C++?

Classes and objects are closely related in C++. A class serves as a template for creating objects, and objects are created using the blueprint provided by a class. Changes made to a class will affect all objects created from it, but each object has its own unique set of properties and behaviors.

3. Can a class have multiple objects in C++?

Yes, a class can have multiple objects in C++. Each object is created using the same class structure but can have different values for its properties. This allows for efficient and organized data management in a program.

4. How are classes and objects declared in C++?

In C++, a class is declared using the keyword "class" followed by the class name. Objects are declared using the class name followed by parentheses and a semicolon. For example: class MyClass { // class declaration }; MyClass myObject; // object declaration

5. What is the role of constructors in classes and objects in C++?

Constructors are special functions within a class that are used to initialize objects when they are created. They have the same name as the class and are automatically called when an object is created. Constructors can also be used to set default values for object properties.

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