string字符串分割

vector<string> split(string str,string pattern)
{
vector<string> ret;
if(pattern.empty()) return ret;
size_t start = 0,index = str.find_first_of(pattern,0);
while(index != str.npos)
{
if(start != index)
ret.push_back(str.substr(start,index - start));
start = index + 1;
index = str.find_first_of(pattern,start);
}
string subStr = str.substr(start);
if(!subStr.empty())
{
ret.push_back(str.substr(start));
}
return ret;
}