Program to Check Whether Given Number is Perfect Or Not ?

#include<stdio.h>

int main()
 {

   int num, i = 1, sum = 0;

   printf("Enter a number: ");

   scanf("%d", &num);

   while (i < num) {

      if (num % i == 0) 
     {

         sum = sum + i;

      }

      i++;

   }

   if (sum == num)

      printf("%d is a Perfect Number", i);

   else

      printf("%d is Non Perfect Number", i);

   return 0;

}

 Output:

Enter a number: 6

6 is a Perfect Number

 Examples

The first perfect number is 6, because 1, 2, and 3 are its proper positive divisors, and 1 + 2 + 3 = 6. Equivalently, the number 6 is equal to half the sum of all its positive divisors: ( 1 + 2 + 3 + 6 ) / 2 = 6. The next perfect number is 28 = 1 + 2 + 4 + 7 + 14.