C#: Find perfect numbers within a given range of number

C# Sharp For Loop: Exercise-28 with Solution

Write a C# Sharp program to find the ‘perfect’ numbers within a given number range.

Visual Presentation:

Sample Solution:

C# Sharp Code:

using System;  // Importing necessary namespace

public class Exercise28  // Declaration of the Exercise28 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
        int mn, mx;  // Declaration of variables mn and mx as integers

        Console.Write("\n\n");  // Displaying new lines
        Console.Write("Find perfect numbers within a given range:\n");  // Displaying the purpose of the program
        Console.Write("------------------------------------------------------");  // Displaying a separator
        Console.Write("\n\n");  // Displaying new lines

        Console.Write("Input the starting range or number : ");  // Prompting the user to input the starting range
        mn = Convert.ToInt32(Console.ReadLine());  // Reading the starting range entered by the user

        Console.Write("Input the ending range of number : ");  // Prompting the user to input the ending range
        mx = Convert.ToInt32(Console.ReadLine());  // Reading the ending range entered by the user

        Console.Write("The Perfect numbers within the given range : ");  // Displaying a message

        // Loop to find perfect numbers within the given range
        for (n = mn; n <= mx; n++)
        {
            i = 1;  // Initializing i to 1
            sum = 0;  // Initializing sum to 0

            // Loop to calculate the sum of divisors for each number in the range
            while (i < n)
            {
                if (n % i == 0)  // Checking if 'i' is a divisor of 'n'
                    sum = sum + i;  // Calculating the sum of divisors
                i++;  // Incrementing 'i'
            }

            // Checking if the sum of divisors is equal to the original number
            if (sum == n)
                Console.Write("{0} ", n);  // Displaying the perfect number
        }

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

Sample Output:

Find perfect numbers within a given number of range:                                                                                                         
------------------------------------------------------                                                                                                         
Input the starting range or number : 1                                                                                                         
Input the ending range of number : 20                                                                                                         
The Perfect numbers within the given range : 6   

Flowchart:

C# Sharp Code Editor:

Contribute your code and comments through Disqus.

Previous: Write a C# Sharp Program to check whether a given number is perfect number or not.
Next: Write a C# Sharp Program to check whether a given number is an Armstrong number or not.