Compile time #3 itoa (number to string)
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| using namespace std;
constexpr char ord[] = "0123456789abcdefghijklmnopqrstuvwxyz";
using integer = unsigned long long;
template <integer X, integer Base = 10>
struct itoax {
static constexpr size_t digits() {
if (X == 0) return 1;
auto q = X;
size_t size = 0;
while (q > 0) {
q /= Base;
size++;
}
return size;
}
static constexpr auto value_array = []() constexpr {
std::array<char, digits() + 1> a{};
if (X == 0) {
a[0] = '0';
a[1] = '\0';
}
else {
auto q = X;
auto index = digits() - 1;
a[index] = '\0';
while (q > 0) {
a[index--] = ord[q % Base];
q /= Base;
}
}
return a;
}();
static constexpr const char* value = value_array.data();
};
|
