Seven boom game by tracking each decimal digit separately instead of looking at the actual number and computing

sevenboom.cpp

#include <memory>
#include <ranges>
#include <iostream>

class Digit {
	unsigned char val, sevenCount;
	std::unique_ptr<Digit> moreSignificant;
public:
	Digit(unsigned char startVal) : val(startVal), sevenCount(startVal % 7) {}
	void inc() {
		if (++sevenCount >= 7)
			sevenCount = 0;
		if (++val > 9) {
			val = 0;
			if (moreSignificant)
				moreSignificant->inc();
			else
				moreSignificant = std::make_unique<Digit>(1);
		}
	}
	bool hasSeven() {
		return val == 7 || (moreSignificant ? moreSignificant->hasSeven() : false);
	}
	bool isDivisibleBySeven() {
		return sevenCount == 0;
	}
};

int main() {
	Digit num(0);
	for (unsigned long long i : std::ranges::views::iota(1ULL, 1000ULL)) { /* while (true) */
		num.inc();
		if (num.hasSeven() || num.isDivisibleBySeven())
			std::cout << "BOOM" << std::endl;
		else
			std::cout << i << std::endl;
	}
}