added f_to_string

to_string.hpp

@@ -15,7 +15,7 @@
  * @tparam N Number to convert
  * @tparam base Desired base, can be from 2 to 36
  */
-template<auto N, unsigned int base, typename char_type,
+template<auto N, int base, typename char_type,
     std::enable_if_t<std::is_integral_v<decltype(N)>, int> = 0,
     std::enable_if_t<(base > 1 && base < 37), int> = 0>
 class to_string_t {
@@ -23,7 +23,7 @@ class to_string_t {
     // fits to the number perfectly.
     char_type buf[([]() constexpr noexcept {
                        unsigned int len = N > 0 ? 1 : 2;
-                       for (auto n = N < 0 ? -N : N; n; len++, n /= base);
+                       for (auto n = N; n; len++, n /= base);
                        return len;
                    }())] = {};
 
@@ -35,8 +35,8 @@ class to_string_t {
         auto ptr = end();
         *--ptr = '\0';
         if (N != 0) {
-            for (auto n = N < 0 ? -N : N; n; n /= base)
+            for (auto n = N; n; n /= base)
-                *--ptr = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ"[n % base];
+                *--ptr = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ"[(N < 0 ? -1 : 1) * (n % base)];
             if (N < 0)
                 *--ptr = '-';
         } else {
@@ -68,7 +68,7 @@ class to_string_t {
 /**
  * Simplifies use of `to_string_t` from `to_string_t<N>()` to `to_string<N>`.
  */
-template<auto N, unsigned int base = 10, typename char_type = char>
+template<auto N, int base = 10, typename char_type = char>
 constexpr to_string_t<N, base, char_type> to_string;
 
 #endif // TCSULLIVAN_TO_STRING_HPP_