习题6-3 使用函数输出指定范围内的完数

 1 #include <stdio.h>
 2 
 3 int factorsum(int number);
 4 void PrintPN(int m, int n);
 5 
 6 int main()
 7 {
 8     int i, m, n;
 9 
10     scanf_s("%d %d", &m, &n);
11     if (factorsum(m) == m) printf("%d is a perfect number\n", m);
12     if (factorsum(n) == n) printf("%d is a perfect number\n", n);
13     PrintPN(m, n);
14 
15     return 0;
16 }
17 
18 /* 你的代码将被嵌在这里 */
19 int factorsum(int number)
20 {
21     int sum = 0;
22     if (number == 1)
23     {
24         return 1;
25     }
26     for (int i = 1; i < number; i++)
27     {
28         if (number%i==0)
29         {
30             sum = sum + i;
31         }
32     }
33 
34     return sum;
35 }
36 
37 void PrintPN(int m, int n)
38 {
39     int is_factorsum = 0;
40     int j;
41     for (int i = m; i <=n; i++)
42     {
43         if (factorsum(i) == i)
44         {
45             printf("%d = 1", i);
46             for (j = 2; j < i; j++)
47             {
48                 if (i % j == 0)
49                 {
50                     printf(" + %d", j);
51                 }
52             }
53             printf("\n");
54             is_factorsum = 1;
55         }
56     }
57     if (is_factorsum == 0)
58     {
59         printf("No perfect number\n");
60     }    
61 }