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=1＋2＋3.编程　　　找出1000以内的所有完数。-If a number is exactly equal to the sum of its factors, this number is called " complete number."　For example, 6 = 1+2+3 program to find all finished within a few 1000.