Finding a Perfect number using C++

Perfect Number: Perfect number is a positive real number which is the sum of its all positive divisors without itself.

Example: $6$ is a perfect number. The divisor of $6$ are $1, 2, 3$.

                  The sum of its divisors are : $1 + 2 + 3 = 6$

                 $28$ is a perfect number. The divisors of $28$ are $1, 2, 4, 7, 14$.

                 The sum of its divisors are : $1 + 2 + 4 + 7 + 14 = 28$

                 Some other perfect numbers are: $496, 8128$, etc  

Algorithm:

1. Find the number of divisors of the number

2. Add all the divisors 

3. Check the addition of the numbers is equivalent to that number or not

4. If equivalent then perfect number

5. If not equivalent not a perfect number 

#include "iostream"
#include "conio.h"
#include "math.h"

using namespace std;


int main()                 //Start of main
{

 int n, i=1, u=1, sum=0;
 cout << "Enter a range to find the perfect numbers :" ;
 cin >> n;
 while(i<=n)
 {                                  // start of first loop.

   while(u<=n)
   {                               //start of second loop.
     if(u<i)
     {
      if (i%u == 0)
        sum = sum + u;
      }                          // End of the if statement
     u++;
    }                            // End of second loop
   if (sum == j)
    {
     cout << i << "is a perfect number" << "\n";
    }
    i++;
    u = 1 ;  sum = 0;
   }                           // End of the First loop
     return(0);
}                             // End of main

Input: Range := 500

Output: Perfect number := 6, 28, 496

Input: Range := 10000

Output: Perfect number := 6, 28, 496, 8128