A
constructor is a special method of class, which is invoked automatically,
whenever an object of a class is created.
It has the same name as its class and resides similar to a method. A constructor has the following
characteristics.
Ø
It doesn’t have any return type not even void
Ø
The constructor can be declared as public
Ø
It can be overloaded
Ø
It is normally used to initialize the member of
the object
Different
types of Constructors:
1)
Default Constructor: A constructor that accepts no parameters is called the
default constructor. If no constructors
are defined for a class, the Java system automatically generates the default
constructor.
Example:
class
Time1
{
int hour,min,sec;
public Time1()
{
hour=10;
min=45;
sec=23;
}
void printdata()
{
System.out.println(hour+"hours:"+min+"minutes:"+sec+"seconds");
}
}
class
const1
{
public static void main(String[]
args)
{
Time1 t=new Time1();
t.printdata();
}
}
O/P: 10hours:45minutes:23seconds
2)
Parameterized Constructor: A constructor that takes arguments as parameters
is called parameterized constructor. If
any constructors are defined by a class with the parameters, Java will not
create a default constructor for the class.
Example:
class
Time1
{
int hour,min,sec;
public Time1(int h,int m,int s)
{
hour=h;
min=m;
sec=s;
}
void printdata()
{
System.out.println(hour+"hours:"+min+"minutes:"+sec+"seconds");
}
}
class
const2
{
public static void main(String[]
args)
{
Time1 t=new
Time1(10,9,4);
t.printdata();
}
}
O/P: 10hours:9minutes:4seconds
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