fmt.hpp
constexpr std::size_t fmtLength(int i) {
  std::size_t digits{i < 0 ? 1u : 0u};
  while (i != 0) {
    i /= 10;
    ++digits;
  }
  return digits;
}
// Number of characters needed to represent i, formatted as a base-10 integer.
Number of characters needed to represent i, formatted as a base-10 integer.
Number of characters needed to represent i formatted as a base - 10 integer .
constexpr std::size_t fmtLength(int i) {
  std::size_t digits{i < 0 ? 1u : 0u};
  while (i != 0) {
    i /= 10;
    ++digits;
  }
  return digits;
}
constexpr std :: size_t fmtLength ( int i ) { std :: size_t digits { i < 0 ? 1u : 0u } ; while ( i != 0 ) { i /= 10 ; ++ digits ; } return digits ; }
Number of characters needed to represent i, formatted as a base-10 integer.
Number of characters needed to represent i formatted as a base - 10 integer .