Method substr

source/core/StarString.cpp:739–761

}

String String::substr(size_t position, size_t n) const {
  auto len = size();
  if (position > len)
    throw OutOfRangeException(strf("out of range in String::substr({}, {})", position, n));

  if (position == 0 && n >= len)
    return *this;

  String ret;
  ret.reserve(std::min(n, len - position));

  auto it = begin();
  std::advance(it, position);

  for (size_t i = 0; i < n; ++i) {
    if (it == end())
      break;
    ret.append(*it);
    ++it;
  }

  return ret;
}

void String::erase(size_t pos, size_t n) {
  String ns;