Constructors

Constructor is a special type of method that is used to initialize the state of object.

It provides the values to the data members at the time of object creation that is why it is known as constructor.

Characteristics of constructor

1. A constructor must have the same name as of its class.

2. It is invoked at the time of object creation and used to initialize the state of an object.

3. It does not have an explicit return type.

Types of constructor

1. Default or no-argument constructor.

2. Parameterized constructor.

Default or no-argument constructor

A constructor with no parameter is known as default or no-argument constructor.

If no constructor is defined in the class then compiler automatically creates a default constructor at the time of compilation.

Syntax

Class_name()

{
//optional block of code

}

Parameterized constructor

A constructor with one or more arguments is known as parameterized constructor.

Parameterized constructor is used to provide values to the object properties.

By use of parameterized constructor different objects can be initialize with different states.

 Syntax

class ClassName

{ .......

ClassName(list of parameters) //parameterized constructor

{ .......

 }

....... }

Important points Related to Parameterized Constructor

•      Whenever we create an object using parameterized constructor, it must be define parameterized constructor otherwise we will get compile time error.

•      Whenever we define the objects with respect to both parameterized constructor and default constructor, It must be define both the constructors.

•      In any class maximum one default constructor but 'n' number of parameterized constructors.

Difference between Method and Constructor