5) Write a Java program that checks given number is perfect number or not using constructor instance variable.

 source file name:  NumberDemo.java

class A

{

int y;

public A(int n)

    {

     y=n;

    }

public void divdisp()

{

int d=1;

while(d<y)

{

if(y%d==0)

System.out.print(d+" ");

d++;

}

}

public void perfectno()

{

int d=1;

int sum=0;

while(d<y)

{

if(y%d==0)

sum=sum+d;

d++;

}

if(sum==y)

System.out.println("\n"+y+" number perfect no");

else

System.out.println("\n"+y+" number is not perfect no");

}

}

class NumberDemo

{

public static void main(String as[])

{

int n=Integer.parseInt(as[0]);

A ob=new A(n);

System.out.println("divisors are:");

ob.divdisp();

ob.perfectno();

}

}

output :

D:\JavaPrograms\Constructors>javac NumberDemo.java

D:\JavaPrograms\Constructors>java NumberDemo 14

divisors are:

1 2 7

14 number is not perfect no

D:\JavaPrograms\Constructors>java NumberDemo 28

divisors are:

1 2 4 7 14

28 number perfect no