面试题 35 第一个出现的字符

char firstNotrepeat(char *str){

	if(str == NULL) return '\0';
	int hash[256];
	memset(hash, 0, sizeof(int)*256);
	
	char *p = str;
	while(*p != '\0'){
		++hash[*p];
		++p;
	}
	p = str;
	while(*p != '\0'){
		if(hash[*p] == 1)
			return *p;
		p++;
	}
	
	return '\0';
}