User-defined binary literal in C++11

binary_literal.cc

#include <iostream>
// http://stackoverflow.com/questions/537303/binary-literals

template<char... digits>
struct conv2bin;

template <char... digits>
constexpr int operator"" _b() {
	return conv2bin<digits...>::value;
}

template <>
constexpr int operator"" _b<'0'>() {
	return 0;
}

template <>
constexpr int operator"" _b<'1'>() {
	return 1;
}

template<char high, char... digits>
struct conv2bin<high, digits...> {
	static constexpr int value = operator"" _b<high>() <<
		sizeof...(digits) ^ conv2bin<digits...>::value;
};

template<char high>
struct conv2bin<high> {
	static constexpr int value = operator"" _b<high>();
};

int main() {
	std::cout << 0_b << std::endl;
	std::cout << 101_b << std::endl;
	std::cout << 000111101_b << std::endl;
	std::cout << 11111111111111111111111111111111_b << std::endl;
	return 0;
}

Nice!

I referenced your work in my answer to "How to get smallest variable with C++11 user defined literals" here: https://stackoverflow.com/a/53702658/1353336