求范围内的完数

描述

一个数如果恰好等于它的因子之和，这个数就称为"完数"。 例如，6的因子为1、2、3，而6=1+2+3，因此6是"完数"。 编程序找出N之内的所有完数，并按下面格式输出其因子：

6 its factors are 1 2 3 (行末有空格)

输入  1000

输出   

6 its factors are 1 2 3 
28 its factors are 1 2 4 7 14 
496 its factors are 1 2 4 8 16 31 62 124 248 

#include <iostream>
using namespace std;

int main()
{
	int N, num = 0;
	cin >> N;
	for (int i = 2; i <= N; i++)
	{
		for (int j = 1; j < i; j++)
		{
			if (i % j == 0)
			{
				num += j;
			}
		}
		if (num == i)
		{
			cout << i << " its factors are ";
			for (int k = 1; k < i; k++)
			{
				if (i % k == 0)
				{
					cout << k << " ";
				}
			}
			cout << endl;
		}
	
		num = 0;
	}
	return 0;
}