大数的加法运算，杭电oj-1002

 1 #include<stdio.h>
 2 #include<string.h>
 3 #define max(a, b) a > b ? a:b
 4 
 5 char a[1024];
 6 char b[1024];
 7 char c[1024];
 8 int i;
 9 
10 void reverse(char *a)
11 {
12     int aa = strlen(a);
13     char t;
14     for(i=0; i<aa/2; i++)
15     {
16         t = a[i];
17         a[i] = a[aa-1-i];
18         a[aa-1-i] = t;
19     }
20 }
21 void add(char *a, char *b, char *c)
22 {
23         int cc = 0, aa = strlen(a), bb = strlen(b);
24         int len = max(aa, bb);
25            for(i=0; i<aa; i++)
26            {
27             a[i] = a[i]-‘0‘;
28         }
29            for(i=0; i<bb; i++)
30         {
31               b[i] = b[i]-‘0‘;
32         }
33         for(i=0; i<len; i++)
34         {
35             c[i] = (a[i]+b[i]+cc) % 10 + ‘0‘;
36             cc = (a[i]+b[i]+cc) / 10;
37         }
38            if(cc) c[i++] = cc + ‘0‘;
39           c[i] = ‘\0‘;
40 }
41 void print(char *c)
42 {
43     for(i = strlen(c)-1; i>=0; i--)
44         printf("%c", c[i]);        
45         printf("\n");
46 }
47 main()
48 {
49     int n, j;
50     scanf("%d", &n);
51     for(j=1; j<=n; j++)
52     {
53         memset(a, 0, sizeof(a));
54         memset(b, 0, sizeof(b));
55         memset(c, 0, sizeof(c));
56         scanf("%s %s", a, b);
57         printf("Case %d:\n", j);
58         printf("%s + %s = ", a, b);
59         reverse(a), reverse(b);
60         add(a, b, c);
61         print(c);
62           if(j != n) printf("\n");
63     }
64     
65 }