#include <stdio.h>
  

  #include <stdlib.h>
  

  #include <string.h>
  

  #define N 10
  

  

  int main(void)
  

  {
  

  char src[N];
  

  scanf("%s", src);
  

  int len = strlen(src);
  

  char* dest = (char *)malloc(sizeof(char) * len);
  

  char* s = &src[len - 1];
  

  char* d = dest;
  

  while (len-- != 0)
  

  *d++ = *s--;
  

  printf("%s\n", dest);
  

  dest = NULL; // 这里为什么不用free(dest)? 这样做的效果是否和free(dest)等同?
  

  return 0;
  

  }