C#: Check whether a given number is perfect number or not

C# Sharp For Loop: Exercise-27 with Solution

Write a C# Sharp program for checking if a number is a perfect number.

Sample Solution:-

C# Sharp Code:

using System;  // Importing necessary namespace

public class Exercise27  // Declaration of the Exercise27 class
{  
    public static void Main()  // Main method, entry point of the program
    {
        int n, i, sum;  // Declaration of variables n, i, and sum as integers

        Console.Write("\n\n");  // Displaying new lines
        Console.Write("Check whether a given number is a perfect number or not:\n");  // Displaying the purpose of the program
        Console.Write("--------------------------------------------------------");  // Displaying a separator
        Console.Write("\n\n");  // Displaying new lines

        Console.Write("Input the number : ");  // Prompting the user to input a number
        n = Convert.ToInt32(Console.ReadLine());  // Reading the number entered by the user

        sum = 0;  // Initializing sum to 0

        Console.Write("The positive divisors : ");  // Displaying a message

        // Loop to find and display the positive divisors of the number
        for (i = 1; i < n; i++)
        {
            if (n % i == 0)  // Checking if 'i' is a divisor of 'n'
            {
                sum = sum + i;  // Calculating the sum of divisors
                Console.Write("{0}  ", i);  // Displaying the divisor
            }
        }

        Console.Write("\nThe sum of the divisors is : {0}", sum);  // Displaying the sum of divisors

        // Checking if the sum of divisors is equal to the original number
        if (sum == n)
            Console.Write("\nSo, the number is a perfect number.");  // Displaying the result if the number is perfect
        else
            Console.Write("\nSo, the number is not a perfect number.");  // Displaying the result if the number is not perfect

        Console.Write("\n");  // Displaying a new line
    }
}

Sample Output:

Check whether a given number is perfect number or not:                                                                                                         
--------------------------------------------------------                                                                                                       
Input the  number : 20                                               
The positive divisor  : 1  2  4  5  10                                                                                                         
The sum of the divisor is : 22                                                                                                         
So, the number is not perfect. 

Flowchart:

C# Sharp Code Editor:

Contribute your code and comments through Disqus.

Previous: Write a program in C# Sharp to find the sum of the series 1 +11 + 111 + 1111 + .. n terms.
Next: Write a C# Sharp Program to find the perfect numbers within a given range of number.