去掉字符串中空格

void rtrim(char *str)
{
  char *ps = str;

  /* find <str> tail */
  while( *ps != '/0' )
    ps++;

  ps—;
  while( (ps >= str) && (*ps == ' ') )
    ps—;

  *(++ps) = '/0';
}

void ltrim(char *str)
{
  char *pd = str;

  while( *str == ' ' )
    str++;

  while( (*pd++ = *str++) != '/0' );
}