用c语言，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1000之内所有的完数，并按下面格式输出其因子：6 its factors are 1 2 3

以下是C知道的回答：

以下是代码实现：

#include <stdio.h>

int main() {
int i, j, sum;
printf("Perfect numbers within 1000 are: \n");
for (i = 1; i <= 1000; i++) {
sum = 0;
for (j = 1; j < i; j++) {
if (i % j == 0) {
sum += j;
}
}
if (sum == i) {
printf("%d its factors are ", i);
for (j = 1; j < i; j++) {
if (i % j == 0) {
printf("%d ", j);
}
}
printf("\n");
}
}
return 0;
}

输出结果如下：

Perfect numbers within 1000 are:
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