Program to find Perfect Number Program in C++

What is a Perfect number:

Perfect Number is a number in which sum of all its positive divisors excluding that number is equals to the number.
For example: 6
Sum of divisors = 1+2+3 = 6

Here we will find perfect numbers between 1 and 500.

Program explanation:

1. Take first number as 1.
2. Use a while loop to generate numbers from 1 to 500 (where 500 is not included as we need the sum of the proper divisors of the number).
3. Using an if statement check if the number divided by ‘i’ gives the remainder as 0 which is basically the proper divisor of the integer.
4. Then the proper divisors of the number are added to the sum variable.
5. If the sum of the proper divisors of the number is equal to the original number, the number is a Perfect number.
6. The final result is printed.

C++ Program to find perfect numbers between 1 and 500:

#include<iostream>
using namespace std;
int main() 
{
int i=1, u=1, sum=0;
while(i<=500)
{ // start of first loop.
    while(u<=500)
    {    //start of second loop.
    if(u<i)
    {
        if(i%u==0 )
            sum=sum+u;
    } //End of if statement
        u++;
    }    //End of second loop
    if(sum==i)
    {
        cout<<i<<" is a perfect number."<<"\n";
    }
    i++;
    u=1; sum=0;
} //End of First loop
return 0;
} //End of main

OUTPUT: