Integer Inquiry

高精度加法，不知错在哪里。、

 1 # include <stdio.h>
 2 # include <string.h>
 3 
 4 # define MAXN 110
 5 
 6 char s[MAXN], sum[MAXN];
 7 
 8 int main()
 9 {
10     int i, len, c, tmp;
11     char ch;
12     
13     while (scanf("%s", s) == 1)
14     {
15           len = strlen(s);
16          
17           if (len == 1 && s[0] == '0')
18              break;
19              
20           for (i = 0; i < len/2; ++i)
21             {
22               ch = s[i];
23                s[i] = s[len-1-i];
24                s[len-1-i] = ch;
25             }
26             
27           for (c = i = 0; i < len; ++i)
28           {
29               tmp = sum[i] + (s[i]-'0') + c;
30               c = (tmp>9 ? 1:0);
31               sum[i] = tmp % 10;
32           }
33           if (c) sum[i] = c;
34                                
35           memset(s, 0, sizeof(s));
36     }
37     for (i = MAXN-1; sum[i] == 0; --i) ;
38     while (i >= 0) putchar(sum[i--]+'0');
39     
40     return 0;
41 }