CONSTRUCTOR

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Constructors:

/*constructor:

* class name and constructor name must be same.

* constructor is invoked when the obj is created.

* constructor have no return type not even void.

Types of constructors

There are two types of constructors:

1. default constructor (no-arg constructor)
2. parameterized constructor

 */

CONSTRUCTOR:

import java.io.*;

class con2

{

con2()

{

System.out.println("This is a default constructor");

}

con2(int a,int b)

{

System.out.println("A value:"+a+"\nB value:"+b);

}

con2(String na,float m)

{

System.out.println("String value:"+na+"\nFloat value:"+m);

}

public static void main(String ar[])throws IOException

{

int x,y;

float s;

String sa;

DataInputStream ss=new DataInputStream(System.in);

x=Integer.parseInt(ss.readLine());

y=Integer.parseInt(ss.readLine());

s=Float.parseFloat(ss.readLine());

sa=ss.readLine();

con2 c0=new con2();

con2 c1=new con2(x,y);

con2 c2=new con2(sa,s);

}

}

//Constructor Using This Key Word

this keyword is used to reference of the instance variable

import  java.io.*;

class con3

{

float t;

int a,b;

con3(int p,int q)

{

this.a=p;

this.b=q;

System.out.println("the val of a,b  "+a+"\t "+b+ "\tadd   :"+(a+b));

}

int rectarea()

{

return a*b;

}

con3(float f)

{

t

this.t=f;

}

float cir(float t)

{

  return (3.14f*t*t);

  }

public static void main(String ar[])throws IOException

{

int k,l;

float s;

DataInputStream d=new DataInputStream(System.in);

k=Integer.parseInt(d.readLine());

l=Integer.parseInt(d.readLine());

s=Float.parseFloat(d.readLine());

con3 c=new con3(k,l);

con3 c1=new con3(s);

System.out.println("the val of rectarea" +c.rectarea());

System.out.println("the val of circle"+c1.cir(s));

}

}

/* Constructor Overloading */

same function name with diff arg

class conovr

{

conovr()  //default constructor

{

System.out.println("This is default constructor");

}

conovr(int x,int y)

{

System.out.println("The int is:" +x+ "\t" +y);f

}

conovr(String m,float n)

{

System.out.println("The string & float:"+m+ "\t" +n);

}

public static void main(String ar[])

{

conovr co=new conovr();

conovr c1=new conovr(100,200);

conovr c2=new conovr(" thuya",123.123f);

}

}

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