求字符串全排列的递归算法

void permutation(char * p_str, char * p_begin)  
{  if(!p_str || !p_begin)  {  return;  }  if('\0' == *p_begin)  {  printf("%s\n", p_str);  }else  {  char * p_ch;  for(p_ch = p_begin; *p_ch != '\0'; ++p_ch)  {  char temp;  /* Swap p_ch and p_begin. */  temp = *p_ch;  *p_ch = *p_begin;  *p_begin = temp;  permutation(p_str, p_begin + 1);  /* Restore p_ch and p_begin. */  temp = *p_ch;  *p_ch = *p_begin;  *p_begin = temp;  }  }  
}  int main(int argc, char * argv[])  
{  char strr[6]="abcde";  permutation(strr, strr);  return 0;  
}