How to implement Perfect Number in Java?

A number is said to be a perfect number if the sum of its positive divisors excluding the number itself is equal to that number. Sounds interesting, isn’t it? In this article, let’s check out how to implement a perfect number in java.

Here is the agenda for this article:

• What is a perfect number in Java?
• Time complexity
• Java program to implement a perfect number

Let’s begin!

What is a Perfect Number in Java?

In simple terms, perfect number is equal to the sum of its proper divisors excluding the number itself. Let me cite an example to help you understand it better. Let’s consider a few examples:
Example1: 6
Positive factors are; 1,2,3,6
Here, the sum of all the factors excluding the number itself is equal to 6.
Example2: 28
Positive factors are; 1,2,4,7,14,28
Again the sum of all the factors excluding the number itself comes out to be 28.

Now that you are clear with the meaning of a perfect number let us move towards our next segment.

Time complexity

The time complexity of a perfect number is √n.

Let us now see the implementation process of a perfect number in Java.

Java Program to Implement a Perfect Number

Code:

import java.util.Scanner;
public class Perfect
{
public static void main(String[] args) 
{
int n, sum = 0;
Scanner s = new Scanner(System.in);
System.out.print("Enter an integer:");
n = s.nextInt();
for(int i = 1; i < n; i++)
{
if(n % i == 0)
{
sum = sum + i;
}
}
if(sum == n)
{
System.out.println("The number is Perfect");
}
else
{
System.out.println("The number is not Perfect");
}    
}
int divisor(int x)
{
return x;
}
}

Output:

Enter an integer: 46
The number is not Perfect

This brings us to the end of this ‘Perfect Number in Java’ article. I have covered one of the most fundamental and important topics of Java. Hope you are clear with all that has been shared with you in this article.

Make sure you practice as much as possible and revert your experience.  

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