- It has the same name as the classname.
- It is used to initialize the object that means it is used to construct the object.
- It does not have any return type.
- It can have arguments.
- The constructor without argument is called default constructor.
- A class can have more than one constructor but they must be different from each other by
- Type of arguments or
- Sequence of arguments
This concept is called constructor overloading.
- It is automatically called when an object is created.
Simple example to explain constructor in program.
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import java.io.*;
class cons
{
int a,b;
cons()//defulat constructer
{
a=10;
b=20;
System.out.println("default constructer");
}
cons(int p,int q)//parametrised constructer
{
a=p;
b=q;
System.out.println("parametrised constructer");
}
cons(int p)//one parametrised constructer
{
a=p;
b=25;
System.out.println("one parametrised constructer");
}
void show()
{
System.out.println("a = "+a);
System.out.println("b = "+b);
}
public static void main(String arg[])throws IOException
{
cons c1=new cons();
c1.show();
cons c2=new cons(10);
c2.show();
cons c3=new cons(100,200);
c3.show();
cons c4=new cons();
c4.show();
cons c5=new cons();
c5.show();
cons c6=new cons(1000,2000);
c6.show();
cons c7=new cons(5000,10000);
c7.show();
}
}
