轮换

#include <stdio.h>
#include <stdlib.h>
#include<string.h>
void shift(char* s, int n)
{
char* p;
char* q;
int len = strlen(s);
if(len==0) return;
if(n<=0 || n==len)
return;

char* s2 = (char*)malloc((len+1)*sizeof(char));
p = s;
q = s2 + n % len;
while(*p)
{
*q++ = *p++;
if(q-s2>=len)
{
*q = '\0';
q = s2;
}
}
strcpy(s,s2);
free(s2);
}
int main()
{
char *s=(char*)malloc(10*sizeof(char));
gets(s);
shift(s,5);
puts(s);
return 0;
}