How to find all perfect numbers in specific interval in c++?

Question

I want to find all perfect numbers from interval x to y. Any help how can I do that ?

Answer 1

Here is a simple solution, it's not very fast, just an example to understand how perfect numbers work.

#include <iostream>

using namespace std;

int main()
{
    int x, y;
    int sum_del;
    cin >> x >> y;
    for(int i = x; i <= y; i++){

        sum_del = 0;

        for (int j = 1; j <= i/2; j++){
            if (i % j == 0)
                sum_del += j;
        }

        if (sum_del == i)
            cout << i << endl;

    }
    return 0;
}