getline

See https://en.cppreference.com/w/cpp/string/basic_string/getline.

./code/getline/main.cc
 1#include <cassert>
 2#include <iostream>
 3#include <sstream>
 4#include <string>
 5
 6int main() {
 7  std::string s = "1,2,3";
 8  std::stringstream ss(s);
 9  std::getline(ss, s, ',');
10  assert(s == "1");
11
12  std::getline(ss, s, ',');
13  assert(s == "2");
14
15  std::getline(ss, s, ',');
16  assert(s == "3");
17  return 0;
18}