Perfect Number in Java


The Java program checks whether a given number is a perfect number or not.

  • The program starts by importing the Scanner class from the java.util package to get user input.
  • Then, the program prompts the user to enter a number and reads the input using the nextInt() method of the Scanner class.
  • Next, the program initializes a variable sum to 0, which will be used to store the sum of factors of the number.
  • The program uses a for loop to iterate through all the numbers from 1 to n - 1, inclusive. For each number, the program checks whether it is a factor of n. If it is, then the program adds it to the sum variable.
  • After the loop ends, the program checks whether the value of sum is equal to n. If it is, then n is a perfect number, and the program prints a message to the console indicating that n is a perfect number. Otherwise, the program prints a message indicating that n is not a perfect number.

Source Code

import java.util.Scanner;
public class perfect {
    //Write a program to check the given number is perfect number or not.
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        System.out.print("Enter The Number : ");
        int n = in.nextInt();//6
        int sum=0;
        for (int i = 1; i <n; i++) {
            if(n%i==0){
                sum+=i;//1+2+3
            }
        }
        if(sum==n){
            System.out.println(n + " is a Perfect Number");
        }else {
            System.out.println(n + " is not a Perfect Number");
        }
    }
}
 

Output

Enter The Number : 6
6 is a Perfect Number
Enter The Number : 13
13 is not a Perfect Number
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Basic Programs