#include #include #include #include "say.h" using namespace std; namespace { const string singles_and_teens_names[] = { "zero", "one", "two", "three", "four", "five", "six", "seven", "eight", "nine", "ten", "eleven", "twelve", "thirteen", "fourteen", "fifteen", "sixteen", "seventeen", "eighteen", "nineteen"}; const string tens_names[] = {"twenty", "thirty", "forty", "fifty", "sixty", "seventy", "eighty", "ninety"}; typedef unsigned long long number_t; const number_t twenty{20ULL}; const number_t one_hundred{100ULL}; const number_t one_thousand{1000ULL}; const number_t one_million{one_thousand * one_thousand}; const number_t one_billion{one_thousand * one_million}; const number_t one_trillion{one_thousand * one_billion}; struct { number_t threshold; string name; } const units[] = {{one_billion, "billion"}, {one_million, "million"}, {one_thousand, "thousand"}, {one_hundred, "hundred"}}; void in_english(ostream& english, number_t number) { for (auto unit : units) { if (number >= unit.threshold) { in_english(english, number / unit.threshold); english << ' ' << unit.name; number %= unit.threshold; if (!number) { return; } english << ' '; } } if (number >= twenty) { const number_t tens{number / 10ULL - 2ULL}; english << tens_names[tens]; if (const number_t single{number % 10ULL}) { english << '-' << singles_and_teens_names[single]; } } else { english << singles_and_teens_names[number]; } } } // namespace namespace say { string in_english(number_t number) { if (number >= one_trillion) { throw std::domain_error("argument out of range"); } ostringstream english; ::in_english(english, number); return english.str(); } } // namespace say