文字列 分割 C++ split

ライブラリ 
vector<string> split_str(string s, char c){
    vector<string> ret;
    stringstream ss;
    FOR(i, 0, s.size()){
        if(s[i]==c){
            ret.push_back(ss.str());
            ss.str("");
            ss.clear();
        }else{
            ss << s[i];
        }
    }
    ret.push_back(ss.str());
    return ret;
}

How to use

vector<string> S = split_str("a,b,c", ',');

お供

string join(VS S, char c){
  stringstream ss;
  ll L = S.size();
  rep(i,L){
    if(i) ss << c;
    ss << S[i];
  }
  return ss.str();
}