Program to Find Perfect Number or Not Java Program

Program: 

Write a program to find perfect number or not?

Description:

A perfect number is a positive integer that is equal to the sum
of its proper positive divisors, that is, the sum of its positive
divisors excluding the number itself. Equivalently, a perfect number
is a number that is half the sum of all of its positive divisors.
The first perfect number is 6, because 1, 2 and 3 are its proper
positive divisors, and 1 + 2 + 3 = 6. Equivalently, the number 6
is equal to half the sum of all its positive divisors:
        ( 1 + 2 + 3 + 6 ) / 2 = 6.

Code:

package com.java2novice.algos;

public class IsPerfectNumber {

    public boolean isPerfectNumber(int number){
        
        int temp = 0;
        for(int i=1;i<=number/2;i++){
            if(number%i == 0){
                temp += i;
            }
        }
        if(temp == number){
            System.out.println("It is a perfect number");
            return true;
        } else {
            System.out.println("It is not a perfect number");
            return false;
        }
    }
    
    public static void main(String a[]){
        IsPerfectNumber ipn = new IsPerfectNumber();
        System.out.println("Is perfect number: "+ipn.isPerfectNumber(28));
    }
}

Output:

28
It is a perfect number
Is perfect number: true

• List Of All Java Programs Frequently Asked In Java Interviews