Default constructor is a constructor without any parameter. And default constructor is implemented in two ways:
a. Implicit default constructor
b. Explicit default constructor
a. Implicit default constructor: An implicit constructor that are added by java compiler itself and we don’t need to explicitly specified or define the constructor.
e.g:
class Rectangle()
{
int length;
int breadth;
public:
int area()
{
return(length*breadth);
}
}
void main()
{
Rectangle r1=new Rectangle(); //object created using implicit constructor
cout<<“area of rectangle r1=”<<r1.area();
}
b. Explicit default constructor: explicit constructor which are use to define by the user to explicitly specify or initialize the data members of the class once we define a constructor in a class it overwrites the functionality of default implicit function.
e.g:
class Rectangle()
{
int length;
int breadth;
public:
Rectangle()
{
length=20;
breadth=30;
}
int area()
{
return(length*breadth);
}
}
void main()
{
Rectangle R1=new Rectangle(); //object created using implicit constructor
cout<<“area of rectangle R1=”<<R1.area();
}