/*Perfect number is a positive number which sum of all positive divisors excluding that number is equal to that number. For example 6 is perfect number since divisor of 6 are 1, 2 and 3.  Sum of its divisor is 1 + 2+ 3 = 6*/

using System;  

public class Exercise27  

{  

    public static void Main()

{

  int n,i,sum;

    Console.Write("\n\n");

    Console.Write("Check whether a given number is perfect number or not:\n");

    Console.Write("--------------------------------------------------------");

    Console.Write("\n\n");    

​

   Console.Write("Input the  number : ");

   n= Convert.ToInt32(Console.ReadLine());  

    sum = 0;

   Console.Write("The positive divisor  : ");

    for (i=1;i<n;i++)

      {

      if(n%i==0)

         {

         sum=sum+i;

         Console.Write("{0}  ",i);

         }

       }

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

    if(sum==n)

      Console.Write("\nSo, the number is perfect.");

    else

      Console.Write("\nSo, the number is not perfect.");

    Console.Write("\n");

  }

}

​