text: int matchstar(int c, char * regexp, char * text);
  // 在text 开头找 regexp
  int matchhere(char * regexp, char * text){
  	if (regexp[0] == '\0') return 1;
  	if (regexp[1] == '*') return matchstar(regexp[0],regexp+2,text);
  	if (regexp[0] == '$' && regexp[1] == '\0') return *text++ == '\0';
  	if (*text != '\0' && (regexp[0] == '.' || regexp[0] == *text)) return matchhere(regexp+1,text+1);
  	return 0;
  }	
  //match star
  int matchstar(int c, char * regexp, char * text){
  	do {
  		if (matchhere(regexp,text)) return 1;
  	} while (*text != '\0' && (*text++ == c || c == '.'));
  }
  int match(char *regexp, char *text){
  	if (regexp[0] == '^')
  		return matchhere(regexp+1, text);
  
  	do {
  		if (matchhere(regexp, text))
  			return 1;
  	} while (*text++ != '\0');
  	return 0;
  }