gistfile1.txt

// string::substr
#include <iostream>
#include <string>

int main ()
{
  std::string str="--flag-switches-begin --timezone=\"America/New_York\" --flag-switches-end";

  std::size_t pos1 = str.find("--timezone=\"") + 12;

  std::size_t pos2 = str.find("\" --flag-switches-end") - pos1;

  std::string str2 = str.substr (pos1,pos2);
  
  std::cout << str2 << '\n';

  return 0;
}