字符串常用函数

vector<string> split(const string& str, string cutStr) {
	vector<string> res;
	size_t start = 0;
	size_t stop;
	while ((stop = str.find(cutStr, start)) != string::npos) {
		if (stop > start) {
			res.push_back(str.substr(start, stop-start));	
		}else {
			res.push_back("");
		}
		start = stop + cutStr.length();
	}
	if(start < str.length()) {
		res.push_back(str.substr(start));
	}else {
		res.push_back("");
	}
	return res;
}