Function main

05.22-stdFmtFormatTo1/main.cpp:12–25

using namespace std::literals;

int main()
{
  constexpr auto fmt{"{}, {}"sv};  // #A The format string

  // #B Lookahead the resulting size in bytes
  const auto size = std::formatted_size(fmt, "Hello"sv, "World"sv);

  std::vector<char> buffer(size);  // #C Preallocate the required memory
  std::format_to(buffer.begin(), fmt, "Hello"sv, "World"sv);

  for(const auto& c : buffer) { std::cout << c; }

  std::cout << '\n';
}