Eg
: 1)
/*
Program to demonstrate default constructor */
class
ConstructorDemo1
{
int l;
{
ConstructorDemo1 c1 =new ConstructorDemo1 ();
System.out.println("Area of Square =
" + c1.l*c1.l);
}
}//
end of class ConstructorDemo1
Eg:
2)
/* Program to demonstrate constructor
without parameters */
class
Square
{
int l;
Square() // constructor
{
System.out.println(“Inside constructor
without parameters “);
l = 100;
}
void area()
{
System.out.println(“Area of Square = “ + l
* l);
}
}// End of class Square
class
ConstructorDemo2
{
public static void main(String args[])
Square s = new Square(); // calls
constructor method
s.area();
} // end of main
}
// end of class ConstructorDemo2
Eg
: 3)
/* Program to demonstrate constructor
with parameters */
class
Square
{
int l;
Square(int x) // constructor
{
System.out.println(“Inside constructor with
parameters “);
l = x;
}
void area()
{
System.out.println(“Area of Square = “ + l
* l);
}
}// End of class Square
class
ConstructorDemo3
{
public static void main(String args[])
{
Square s = new Square(100); // calls
constructor method
s.area();
} // end of main
}
// end of class ConstructorDemo3
Eg
: 4)
/* Program to demonstrate multiple
constructors */
class
Rectangle
{
int l,b;
Rectangle() //
{
System.out.println(“Inside constructor
without parameters “);
l = 100;
b = 200;
}
Rectangle(int x) //
{
System.out.println(“Inside constructor with
one parameter “);
l = x;
b = x;
}
Rectangle(int x,int y)
{
System.out.println(“Inside constructor with
two parameters “);
l = x;
b = y;
}
void area()
{
System.out.println(“Area of Square = “ + l
* l);
}
}// End of class Rectangle
class
ConstructorDemo4
{
public static void main(String args[])
{
Rectangle r1 = new Rectangle();
Rectangle r2 = new Rectangle(15);
Rectangle r3 = new Rectangle(50,150);
r1.area();
r2.area();
r3.area();
} // end of main
}
// end of class ConstructorDemo4
