C语言 序列反向互补函数

 1 static char *revers(char *s)
 2 {
 3     int len=strlen(s);
 4     char *s2=(char *)malloc(sizeof(char)*(len+1));
 5     for(int i=len-1; i>=0; i--)
 6     {
 7         switch (s[i])
 8         {
 9                 case 'A':
10                     s2[len-1-i] = 'T'; break;
11                 case 'T':
12                     s2[len-1-i] = 'A'; break;
13                 case 'G':
14                     s2[len-1-i] = 'C'; break;
15                 case 'C':
16                     s2[len-1-i] = 'G'; break;
17                 default:
18                     break;
19             }
20     }
21     return s2;
22 }